Buttiauxella sp. phytase variants

ABSTRACT

Provided herein are variants of  Buttiauxella  sp. phytases that may be used in industrial applications including methods for starch liquefaction, alcohol fermentations and for enhancing phosphate digestion in foods and animal feeds.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No.12/988,363, filed Jan. 31, 2011, now U.S. Pat. No. 8,673,609, which is a371 National Phase application of PCT/US09/41011, filed Apr. 17, 2009,which claims benefit of U.S. Provisional Patent Application No.61/046,324 filed Apr. 18, 2008, the disclosures of which areincorporated herein by reference in its their entirety for all purposes.

SEQUENCE LISTING

The sequence listing submitted via EFS, in compliance with 37 C.F.R.§1.52(e), is incorporated herein by reference. The sequence listing textfile submitted via EFS contains the file “31307WO2_SeqList.txt”, createdon Jan. 22, 2014, which is 24,576 bytes in size.

FIELD OF THE DISCLOSURE

The technology provided herein relates to improved variants ofButtiauxella sp. phytases, nucleic acids encoding the phytases, vectors,host cells containing the nucleic acids and methods for producing thephytases. The phytases encompassed by this disclosure may be used innumerous applications including, e.g., methods for starch liquefaction,alcohol fermentations and for enhancing phosphate digestion in foods andanimal feeds.

BACKGROUND

Phytate is the major storage form of phosphorus in cereals and legumes.However, monogastric animals such as pig, poultry and fish are not ableto metabolise or absorb phytate (or phytic acid) and therefore it isexcreted, leading to phosphorous pollution in areas of intense livestockproduction. Moreover, phytic acid also acts as an antinutritional agentin monogastric animals by chelating metal agents such as calcium, copperand zinc.

In order to provide sufficient phosphates for growth and health of theseanimals, inorganic phosphate is added to their diets. Such addition canbe costly and further increases pollution problems.

Through the action of phytase, phytate is generally hydrolysed to givelower inositol-phosphates and inorganic phosphate. Phytases are usefulas additives to animal feeds where they improve the availability oforganic phosphorus to the animal and decrease phosphate pollution of theenvironment (Wodzinski R J, Ullah A H. Adv Appl Microbiol. 42, 263-302(1996)).

A number of phytases of fungal (Wyss M. et al., Appl. Environ.Microbiol. 65 (2), 367-373 (1999); Berka R. M. et al., Appl. Environ.Microbiol. 64 (11), 4423-4427 (1998); Lassen S. et al., Appl. Environ.Microbiol. 67 (10), 4701-4707 (2001)) and bacterial (Greiner R. et alArch. Biochem. Biophys. 303 (1), 107-113 (1993); Kerovuo et al., Appl.Environ. Microbiol. 64 (6), 2079-2085 (1998); Kim H. W. et al.,Biotechnol. Lett. 25, 1231-1234 (2003); Greiner R. et al., Arch.Biochem. Biophys. 341 (2), 201-206 (1997); Yoon S. J. et al., Enzyme andmicrobial technol. 18, 449-454 (1996); Zinin N. V. et al., FEMSMicrobiol. Lett. 236, 283-290 (2004))) origin have been described in theliterature.

SUMMARY OF THE DISCLOSURE

In a first aspect, embodiments of this disclosure provide phytasevariants which have an amino acid sequence that varies from that of thewild type Buttiauxella sp. phytase (SEQ ID NO: 1), and which have one ormore advantageous properties. Such properties may include but are notlimited to favorable: thermostability; temperature/activity profile;pH/activity profile; specific activity; and pH/protease-sensitivity.

In a further aspect, embodiments of this disclosure relate to a phytasevariant comprising a phytase that contains a substitution at one or morepositions selected from the group consisting of: 75, 76 and 374, whereineach position corresponds to the position of the amino acid sequence ofthe wild type Buttiauxella sp. phytase (SEQ ID NO: 1).

In still another aspect, embodiments of this disclosure provide nucleicacids encoding phytase variants as disclosed herein, as well as vectorsand host cells comprising such nucleic acids. In yet other embodiments,the sequences are employed in processes that yield the phytase variants.

Further, embodiments of this disclosure relate generally to the use ofthe phytase variants for liberating phosphorous from any phytasesubstrate, in particular inorganic phosphate from phytate or phyticacid. Advantageously, phytase variants of this disclosure may be used inindustrial applications including, for example, methods for starchliquefaction and for enhancing phosphate digestion in foods and animalfeeds. Advantageously, phytase variants according to embodiments of thepresent disclosure are useful and used in alcohol fermentationsprocesses and/or productions.

In other aspects, this disclosure relates to enzyme compositionscomprising a phytase variant as described herein, wherein the enzymecomposition is useful for, or used in, commercial applications. In oneembodiment, the enzyme composition may be an animal feed composition. Inother embodiments, the enzyme composition may be used in starchhydrolysis (e.g. liquefaction) processes. In an advantageous embodiment,the variants and/or the enzyme composition may be used in alcoholfermentation processes. In further embodiments, an enzyme compositioncomprising a phytase encompassed by this disclosure will includeadditional enzymes, such as glucoamylases, alpha amylases, protease,cellulases, hemicellulases, lipases, pectinases, pullulanases, glucoseoxidases, beta glucosidases, laccases, oxidases, cutinases,phosphatases, other phytases and combinations thereof.

In a further aspect, embodiments of this disclosure relate to methodsfor producing the phytase variants in a host cell by transforming thehost cell with a DNA construct, advantageously including a promoterhaving transcriptional activity in the host cell, cultivating thetransformed host cell in a suitable culture medium to allow expressionof said phytase and producing the phytase. The method may also includerecovering the produced phytase. In one embodiment, the host cell is abacterial, or a plant cell, or a fungal cell (such as a Trichodermacell, such as T. reesei) or a yeast. In embodiments described herein,the amino acid sequence of the phytase variant shares a minimumpercentage sequence identity to the amino acid sequence identity withSEQ ID NO: 1, e.g., at least 80%, at least 85%, at least 90%, at least95%, at least 96%, at least 97%, at least 98% amino acid sequenceidentity with SEQ ID NO: 1. In an advantageous embodiment of thisdisclosure, the phytase has the sequence of SEQ ID NO: 2.

The enzyme of the present invention is that defined in the claims andalso herein. The enzyme of the present invention also encompasses activepolypeptides that are co- or post-translationally processed duringexpression, for example by signal peptide cleavage. Post-translationalcleavage may also occur at the C-terminal. Therefore in a preferredembodiment the effective fragment thereof (also referred to asfunctional fragment thereof) is the mature polypeptide produced by thenative host or a suitable appropriate expression host.

Thus, in one aspect, the phytase is characterised in that it comprisesan amino acid sequence that is expressed from or is expressable from allor part of the nucleotide sequence encoding the variants defined herein.

In general, in one aspect phytase variant having improved thermalactivity of at least about 5° C. as compared to wild type Buttiauxellasp. phytase (SEQ ID NO: 1) is provided. In one embodiment the phytasethe improved thermal activity is at least about 17° C. as compared tothe phytase SEQ ID NO: 1. In another embodiment the improved thermalactivity is in a range from about 17 to about 21° C. In a furtherembodiment the improved thermal activity is in a range from about 17.4to about 20.2° C.

In general in a further aspect a thermostable phytase variant isprovided that is capable of retaining greater than 50% of its activityafter exposure to an elevated temperature for 10 minutes at pH 5.5 inbuffer, wherein the elevated temperature is at least about 5° C. higherthan a temperature at which wild type Buttiauxella sp. phytase (SEQ IDNO: 1) retains greater than 50% of its activity. In one aspect theelevated temperature is at least about 20.5° C. higher. In anotheraspect the elevated temperature is in a range from about 20.5° C. toabout 27° C. In a further aspect the elevated temperature is in a rangefrom about 20.2° C. to about 26.8° C.

In general, in another aspect a phytase variant is provided havingphytase activity and an amino acid sequence that varies from the aminoacid sequence of wild type Buttiauxella sp. phytase (SEQ ID NO: 1),wherein the amino acid sequence of the phytase variant comprises avariation at one or more positions corresponding to position 75, 76, 77,198, 367 or 374 of SEQ ID NO: 1. In one embodiment the phytase variantfurther comprises one or more additional variation, wherein thevariation is 92A, 164E/S, 171I/V, 192A or 256A/E/P. In anotherembodiment the variation at one or more of positions 75, 76, 77, 198,367 or 374 respectively is 75P, 76R, 77S, 198R, 367L or 374P and thephytase variant further comprises one or more additional variationwherein the variation is 92A, 164E/S, 171V, 192A or 256A/E/P. In yetanother embodiment the phytase variant further comprises one or moreadditional variation, wherein the one or more additional variationposition is 26, 37, 89, 134, 160, 176, 178, 188, 190, 207, 209, 211,235, 261, 270, 303 or 318. In a further embodiment the one or moreadditional variation at position 26, 37, 89, 134, 160, 176, 178, 188,190, 207, 209, 211, 235, 261, 270, 303 or 318 is respectively 26E, 037Y,089T, 1341/V, 160R, 176K, 178P, 188N, 190E, 207E/T, 209S, 211C, 235V,261E, 270K, 303F or 318D. In another embodiment the phytase variantfurther comprises one or more additional variation, wherein the one ormore additional variation position is 1, 10, 11, 38, 66, 71, 81, 92,109, 111, 119, 120, 121, 141, 142, 152, 155, 193, 214, 239, 245, 248,255, 268, 277, 283, 285, 287, 288, 293, 296, 314, 337, 345, 350, 364,371, 372, 396, 399, 406 or 413. In yet another embodiment the one ormore additional variation at position 1, 10, 11, 38, 66, 71, 81, 92,109, 111, 119, 120, 121, 141, 142, 152, 155, 193, 214, 239, 245, 248,255, 268, 277, 283, 285, 287, 288, 293, 296, 314, 337, 345, 350, 364,371, 372, 396, 399, 406 or 413 is respectively 1S, 10I, 11I, 38S, 66E,71K, 81A, 92E, 109Q, 111G, 119N, 120L, 121E, 141R, 142L, 152M, 155E,193Q, 211C, 214V, 235V, 239K, 245D, 248L, 255A, 261E, 268A/T, 270K,277T, 283D, 285K, 287D, 288A, 293G or 296S.

In general in another aspect a phytase variant is provided havingphytase activity and an amino acid sequence that varies from the aminoacid sequence of wild type Buttiauxella sp. phytase (SEQ ID NO: 1),wherein the amino acid sequence of the phytase variant comprises atleast one variation as compared with SEQ ID NO: 1, and wherein thephytase sequence variation comprises

a) N37Y, S75P, A89T, D92A, T134I, H160R, F164E, T171V, T176K, A178P,S188P, G192A, K198R, K207E, A209S, S248L, Q256Y, A261E, N270K, A374P b)N37Y, G77S, A89T, D92A, T134I, H160R, F164E, T171V, T176K, A178P, S188P,G192A, K198R, K207E, A209S, S248L, Q256Y, A261E, N270K, A374P c) N37Y,S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171I, T176K, A178P, S188P,G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P d) N37Y,A89T, D92A, T134I, F164E, T171V, T176K, A178P, G192A, K207E, A209S,A235V, S248L, Q256P, A261E, N270K, A374P e) S75P, Q76R, A89T, D92A,T134I, H160R, F164E, T171I, T176K, A178P, S188P, G192A, K207E, A209S,S248L, Q256Y, A261E, N270K, A374P f) N37Y, Q76R, A89T, D92A, T134I,H160R, F164E, T171I, T176K, A178P, S188P, G192A, K207E, A209S, S248L,Q256Y, A261E, N270K, A374P g) N37Y, Q76R, A89T, D92A, T134I, F164S,T171V, T176K, A178P, S188P, G192A, K207E, A209S, A235V, S248L, Q256A,A261E, N270K, A374P h) S75P, A89T, D92A, T134I, F164E, T171V, T176K,A178P, S188P, G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K,A374P i) S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171V, T176K,A178P, S188P, G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K,P367L, A374P j) N37Y, A89T, D92A, T134I, F164E, T171I, T176K, A178P,G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P k) N37Y,Q76R, A89T, D92A, T134I, F164E, T171V, T176K, A178P, G192A, K207E,A209S, S248L, Q256Y, A261E, N270K, A374P l) N37Y, Q76R, A89T, D92A,T134I, F164E, T171V, T176K, A178P, G192A, K207E, A209S, S248L, Q256A,A261E, N270K, A374P m) N37Y, S75P, Q76R, A89T, D92A, T134I, F164E,T171V, T176K, A178P, K207E, A209S, A235V, S248L, Q256A, A261E, N270K,A374P n) N37Y, S75P, A89T, D92A, T134I, H160R, F164E, T171V, T176K,A178P, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P o) N37Y,A89T, D92A, T134I, H160R, F164S, T171I, T176K, A178P, S188P, G192A,K207E, A209S, A235V, S248L, Q256E, A261E, N270K, A374P p) A89T, D92A,T134I, H160R, F164E, T171V, T176K, A178P, G192A, K207E, A209S, A235V,S248L, Q256Y, A261E, N270K, A374P q) N37Y, S75P, A89T, D92A, T134I,H160R, F164S, T171V, T176K, A178P, S188P, K207E, A209S, S248L, Q256H,A261E, N270K, A374P r) N37Y, S75P, A89T, D92A, T134I, F164S, T171V,T176K, A178P, S188P, G192A, K207E, A209S, S248L, Q256A, A261E, N270K,A374P s) S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171V, T176K,A178P, G192A, K207E, A209S, S248L, Q256A, A261E, N270K, A374P; or t)N37Y, Q76R, A89T, D92A, T134I, H160R, F164S, T171V, T176K, A178P, G192A,K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P.

In one embodiment the phytase sequence variation comprises N37Y, S75P,Q76R, A89T, D92A, T134I, H160R, F164E, T171I, T176K, A178P, S188P,G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P.

Also provided is a phytase which has at least a minimum percent sequenceidentity and/or percent homology to the phytase(s) disclosed herein,wherein the minimum percent identity and/or homology is at least 50%, atleast 60%, at least 75%, at least 80%, at least 85%, at least 90%, atleast 93%, at least 95%, at least 96%, at least 97%, at least 98% or atleast 99%.

In general in one aspect a phytase variant is provided having phytaseactivity and an amino acid sequence that varies from the amino acidsequence of the wild type Buttiauxella sp. phytase (SEQ ID NO: 1),wherein the amino acid sequence of the phytase variant comprises atleast one variation as compared with SEQ ID NO: 1, and wherein thevariant has a variation at at least any one of the following positions:70, 193, 197, 221 and 407. In one embodiment the variant has at leastthe following variations: N70Y, H193R, F197E, S221P and A407P.

In general, in another aspect a nucleic acid encoding any of thephytase(s) disclosed herein is provided. In another aspect, a vectorcomprising the nucleic acid encoding any of the phytase(s) disclosedherein is provided. In a further aspect a host cell comprising thenucleic acid and/or the vectors described herein are provided.

In general, in another aspect a method of producing a phytase variantaccording to the variants disclosed herein, in a host cell is provided,comprising

a) transforming a host cell with a DNA construct comprising the nucleicacid encoding any of the phytase variants disclosed herein, andb) cultivating the transformed host cell in a suitable culture medium.In one embodiment the host cell is a fungal cell, a bacterial cell or aplant cell.

In one aspect a phytase prepared by the methods disclosed herein isprovided.

In general, in one aspect an enzyme composition comprising at least onephytase as disclosed herein including additionally one or more of aglucoamylase, an alpha-amylase, a protease, a pullulanase, anisoamylase, a cellulase, a hemicellulase, a xylanase, a cyclodextringlycotransferase, a lipase, a laccase, an oxidase, an esterase, acutinase, another phytase or any combinations thereof. In one embodimentthe composition additionally includes an alpha-amylase.

In general, in another aspect the use of a phytase as described hereinor an enzyme composition as described herein, in starch liquefaction,saccharification, fermentation or simultaneoussaccharification-fermentation is provided. In one embodiment the starchliquefaction, saccharification, fermentation or simultaneoussaccharification-fermentation is for production of fermentation alcohol.In another embodiment the alcohol is ethanol or butanol. In yet anotherembodiment a substrate is subjected to the starch liquefaction,saccharification, fermentation or simultaneoussaccharification-fermentation. In one embodiment the substrate comprisesstarch. In another embodiment the substrate comprises a grain or cereal.In a further embodiment the grain or cereal is wheat, barley, rye, oats,maize, sorghum, corn gluten meal, Distillers Dried Grain Solubles(DDGS), wheat bran, wheat middlings, wheat shorts, rice, oat hulls, palmkernel, citrus pulp or combinations thereof. In one embodiment the ricecomprises rice bran or rice hulls.

In general, in another aspect the use of at least one phytase asdisclosed herein as an additive to a food or feed is provided. Inanother aspect the use of at least one phytase as disclosed herein as anadditive to a food or feed containing Distillers Dried Grain Solubles(DDGS).

In general, in a further aspect a method for production of food oranimal feed is provided comprising a step of admixing at least onephytase as disclosed herein or an enzyme composition as disclosed hereinwith another food or feed ingredient to form said food or animal feed.

In general, another aspect a method for production of food or animalfeed is provided comprising a step of spraying at least one phytase asdisclosed herein or an enzyme composition as disclosed herein in liquidform onto said food or animal feed. In one aspect, a method forproduction of food or animal feed comprising a step of mixing at leastone phytase as disclosed herein or an enzyme composition as disclosedherein as a dry product with said food or animal feed.

In another aspect a method for production of animal feed is providedcomprising a step of admixing at least one phytase as disclosed hereinor an enzyme composition as disclosed herein with another food or feedingredient to form said animal feed. In a further aspect a method forproduction of animal feed is provided comprising a step of spraying atleast one phytase as disclosed herein or an enzyme composition asdisclosed herein in liquid form onto said animal feed. In one moreaspect a method for production of animal feed is provided comprising astep of mixing at least one phytase as disclosed herein or an enzymecomposition as disclosed herein as a dry product with said animal feed.

In general, in another aspect a food or animal feed composition isprovided comprising either i) at least one phytase as disclosed hereinor an enzyme composition as disclosed herein and/or ii) a food or animalfeed produced by the method as disclosed herein. In a further aspect ananimal feed composition is provided comprising either i) at least onephytase as disclosed herein or an enzyme composition as disclosed hereinand/or ii) a food or animal feed produced by the method as disclosedherein.

In one aspect a use of at least one phytase as disclosed herein or anenzyme composition as disclosed herein in food or animal feed isprovided. In another aspect, a use of at least one phytase as disclosedherein or an enzyme composition as disclosed herein in an animal feed isprovided.

In general, in another aspect a method of reducing the levels ofphosphorus in animal manure is provided, characterized in that an animalis fed with at least one phytase as disclosed herein or an enzymecomposition as disclosed herein or a feed prepared by the method asdisclosed herein or a composition as disclosed herein, and wherein saidphytase is in an amount effective in converting phytate contained insaid animal feed.

In general, in one aspect a use of at least one phytase as disclosedherein or an enzyme composition as disclosed herein or a feed preparedby the method as disclosed herein or a composition as disclosed herein,in the manufacture of an animal feed to reduce the levels of phosphorusin manure from the animal fed with said phytase polypeptide is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. shows the amino acid sequence of a wild-type Buttiauxella sp.P1-29 phytase, (“BP-WT”), (SEQ ID NO: 1).

FIG. 2. shows the amino acid sequence of one advantageous variantaccording to the present disclosure (SEQ ID NO: 2).

FIG. 3. shows the nucleic acid sequence of a wild-type Buttiauxella sp.P1-29 (SEQ ID NO: 3).

FIG. 4. shows the nucleic acid sequence of an advantageous variantaccording to the present disclosure shown in FIG. 2 (SEQ ID NO: 4).

FIG. 5 presents the amino acid sequences for three enzymes according tothe present invention (BP 110, BP-111 and BP-112), as well as thesequences for BP-17 and the wt sequence.

FIGS. 6A and 6B show the resistance of the phytases originating fromButtiauxella, variants BP-17, BP-110, BP-111, and BP-112, and of PhyzymeXP, Natuphos, and Ronozyme P against increasing concentrations ofpepsin. Data are relative to incubation at pH 2 without pepsin. FIG. 6Ashows: all data points, FIG. 6B shows: same data but showing only morethan 70% recovery.

FIG. 7 shows a schematic diagram of the feed processing equipment (feedpelleting) used in Example 11.

FIG. 8 shows data graphs.

FIG. 9 shows data graphs.

FIG. 10 shows data graphs.

FIG. 11 shows data graphs.

FIG. 12 shows data graphs.

FIG. 13 shows data graphs.

FIG. 14 shows data graphs.

FIG. 15 shows HPLC data plots.

FIG. 16 shows HPLC data plots.

DETAILED DESCRIPTION OF THIS DISCLOSURE

Disclosed herein are variants of Buttiauxella sp. phytases that may beused in industrial applications including methods for starchliquefaction, alcohol fermentations and for enhancing phosphatedigestion in foods and animal feeds. In particular, phytase variantsaccording to the present disclosure are very useful for phytatedegradation in starch liquefaction steps in fuel ethanol productionprocesses. The variants of this disclosure comprise one or morevariations (including substitutions, insertions and deletions) from theamino acid sequence of the wild type Buttiauxella sp. phytase (SEQ IDNO: 1). In an advantageous embodiment, the amino acid sequence of thevariant comprises at least one variation as compared to the amino acidsequence of SEQ. ID NO: 1, and the at least one variation is at one, twoor three positions selected from the group consisting of: 75, 76 and374, wherein each position corresponds to the position of the amino acidsequence of SEQ ID NO: 1.

For example, advantageously the variation in the phytase variantsaccording to embodiments of the present disclosure is selected from thegroup consisting of: S75, Q76 and A374 corresponding to SEQ ID NO: 1.

In advantageous embodiments of the present disclosure, the variation inthe phytase variant is a substitution and the substitution can beselected from the group consisting of: S75P, Q76R and A374P wherein eachposition corresponds to the position of the amino acid sequence of SEQID NO: 1.

In further advantageous embodiments, phytase variants according to thepresent disclosure comprises a further variation at one or morepositions selected from the group consisting of: N37, G77, H160, F164,T171, S188, G192, K198, A235, Q256 and/or P367 wherein each positioncorresponds to the position of the amino acid sequence of SEQ ID NO: 1.

In yet other advantageous embodiments, the variation in phytase variantsaccording to the present disclosure is a substitution and thesubstitution can be at one or more positions selected from the groupconsisting of: N37Y, G77S, H160R, F164E, F164S, T171V, T171I, S188P,G192A, K198R, A235V, Q256P, Q256A, Q256E and/or P367L.

In other advantageous embodiments, phytase variants according to thepresent disclosure comprises further a variation at one or morepositions selected from the group consisting of: A89, D92, T134, F164,T176, A178, K207, A209, S248, Q256, A26E and/or N270.

Further, in other advantageous embodiments, phytase variants accordingto the present disclosure comprises a further variation at one or morepositions selected from the group consisting of: A89T, D92A, T134I,F164S, T176K, A178P, K207E, A209S, S248L, Q256Y, A261E and/or N270K.

In yet other advantageous embodiments, phytase variants according to thepresent disclosure comprises a sequence of SEQ ID NO: 2.

Advantageous phytase variants according to the present disclosurecomprises a sequence containing variations selected from the groupconsisting of:

-   -   a) N37Y, S75P, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, S188P, G192A, K198R, K207E, A209S, S248L, Q256Y, A261E,        N270K, A374P    -   b) N37Y, G77S, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, S188P, G192A, K198R, K207E, A209S, S248L, Q256Y, A261E,        N270K, A374P

c) N37Y, S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171I, T176K,A178P, S188P, G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K,A374P

-   -   d) N37Y, A89T, D92A, T134I, F164E, T171V, T176K, A178P, G192A,        K207E, A209S, A235V, S248L, Q256P, A261E, N270K, A374P    -   e) S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171I, T176K,        A178P, S188P, G192A, K207E, A209S, S248L, Q256Y, A261E, N270K,        A374P    -   f) N37Y, Q76R, A89T, D92A, T134I, H160R, F164E, T171I, T176K,        A178P, S188P, G192A, K207E, A209S, S248L, Q256Y, A261E, N270K,        A374P    -   g) N37Y, Q76R, A89T, D92A, T134I, F164S, T171V, T176K, A178P,        S188P, G192A, K207E, A209S, A235V, S248L, Q256A, A261E, N270K,        A374P    -   h) S75P, A89T, D92A, T134I, F164E, T171V, T176K, A178P, S188P,        G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P    -   i) S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, S188P, G192A, K207E, A209S, A235V, S248L, Q256Y, A261E,        N270K, P367L, A374P    -   j) N37Y, A89T, D92A, T134I, F164E, T171I, T176K, A178P, G192A,        K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P    -   k) N37Y, Q76R, A89T, D92A, T134I, F164E, T171V, T176K, A178P,        G192A, K207E, A209S, S248L, Q256Y, A261E, N270K, A374P        -   l) N37Y, Q76R, A89T, D92A, T134I, F164E, T171V, T176K,            A178P, G192A, K207E, A209S, S248L, Q256A, A261E, N270K,            A374P    -   m) N37Y, S75P, Q76R, A89T, D92A, T134I, F164E, T171V, T176K,        A178P, K207E, A209S, A235V, S248L, Q256A, A261E, N270K, A374P    -   n) N37Y, S75P, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P    -   o) N37Y, A89T, D92A, T134I, H160R, F164S, T171I, T176K, A178P,        S188P, G192A, K207E, A209S, A235V, S248L, Q256E, A261E, N270K,        A374P    -   p) A89T, D92A, T134I, H160R, F164E, T171V, T176K, A178P, G192A,        K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P    -   q) N37Y, S75P, A89T, D92A, T134I, H160R, F164S, T171V, T176K,        A178P, S188P, K207E, A209S, S248L, Q256H, A261E, N270K, A374P    -   r) N37Y, S75P, A89T, D92A, T134I, F164S, T171V, T176K, A178P,        S188P, G192A, K207E, A209S, S248L, Q256A, A261E, N270K, A374P    -   s) S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, G192A, K207E, A209S, S248L, Q256A, A261E, N270K, A374P    -   t) N37Y, Q76R, A89T, D92A, T134I, H160R, F164S, T171V, T176K,        A178P, G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K,        A374P.

Embodiments of this disclosure also include variants of any of thephytases set forth in sequences a) to t), which have phytase activityand an amino acid sequence having a percent sequence identity and/orpercent homology of at least 50%, at least 60%, at least 75%, at least80%, at least 85%, at least 90%, at least 93%, at least 95%, at least96%, at least 97%, at least 98%, and at least 99% as compared to each ofthe phytase variants set forth in sequences a) to t).

Amino acids are referred to herein using the name of the amino acid, thethree letter abbreviation or the single letter abbreviation. The tablebelow provides a list of the standard amino acids together with theirabbreviations.

Alanine A Ala Cysteine C Cys Aspartic acid D Asp Glutamic acid E GluPhenylalanine F Phe Glycine G Gly Histidine H His Isoleucine I IleLysine K Lys Leucine L Leu Methionine M Met Asparagine N Asn Proline PPro Glutamine Q Gln Arginine R Arg Serine S Ser Threonine T Thr Valine VVal Tryptophan W Trp Tyrosine Y Tyr Cysteine C Cys Aspartic acid D Asp

In addition to the specific amino acid variations and nucleic acidsencoding the variations, conservative amino acid substitutions of thevariations are provided herein. Such substitutions are those which areconservative, for example, wherein the variant amino acid is replaced byanother amino acid of the same general type. Amino acids can beclassified as acidic, basic, neutral and polar, or neutral and nonpolarand/or aromatic, depending on their side chain. Preferred substitutionsof a variant amino acid position include those that have one or moreclassifications that are the same as the variant amino acid at thatposition. Thus, in general, amino acids Lys, Arg, and His are basic;amino acids aspartic and glutamic are acidic; amino acids Ser, Thr, Cys,Gln, and Asn are neutral polar; amino acids Gly, Ala, Val, Ile, and Leuare nonpolar aliphatic, and amino acids Phe, Trp, and Tyr are aromatic.Gly and Ala are small amino acids and Val, Ile and Leu are alipathicamino acids.

Unless defined otherwise herein, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which this disclosure belongs. Singleton, et al.,DICTIONARY OF MICROBIOLOGY AND MOLECULAR BIOLOGY, 20 ED., John Wiley andSons, New York (1994), and Hale & Marham, THE HARPER COLLINS DICTIONARYOF BIOLOGY, Harper Perennial, N.Y. (1991) provide one of skill with ageneral dictionary of many of the terms used in this disclosure.

This disclosure is not limited by the exemplary methods and materialsdisclosed herein, and any methods and materials similar or equivalent tothose described herein can be used in the practice or testing ofembodiments of this disclosure. Numeric ranges are inclusive of thenumbers defining the range. Unless otherwise indicated, nucleic acidsequences are written left to right in 5′ to 3′ orientation; amino acidsequences are written left to right in amino to carboxy orientation,respectively.

The headings provided herein are not limitations of the various aspectsor embodiments of this disclosure which can be had by reference to thespecification as a whole. Accordingly, the terms defined immediatelybelow are more fully defined by reference to the specification as awhole.

Phytic acid (myo-inositol hexakisphosphate) is an important constituentin cereals, legumes and oilseed crops. The salt form, phytate, is themajor storage form of phosphorous in these plants.

Phytases catalyse phosphate monoester hydrolysis of phytic acid whichresults in the step-wise formation of myo-inositol pentakis-, tetrakis-,tris-, bis- and monophosphates, as well as the liberation of inorganicphosphate.

The terms “phytase variant” or “variant” or “modified form” refer to aphytase enzyme with an amino acid sequence derived from the amino acidsequence of a parent phytase having one or more amino acidsubstitutions, insertions, and/or deletions, which together are referredto as “mutations”.

The terms “parent phytase” or “parent enzyme” refer to a phytase enzymefrom which a phytase variant is derived. A parent phytase can be a wildtype phytase or another phytase variant. In particular, in the presentinvention, a “parent phytase” may be derived from a Buttiauxella sp.Suitably, the “parent phytase” is derived from Buttiauxella strain P1-29as described herein which, preferably has the amino acid sequence setout herein.

As used herein, the term “phytase” or “phytase activity” refers to aprotein or polypeptide which is capable of catalyzing the hydrolysis ofphytate to (1) myo-inositol and/or (2) mono-, di-, tri-, tetra- and/orpenta-phosphates thereof and (3) inorganic phosphate. For example,enzymes having catalytic activity as defined in Enzyme Commission ECnumber 3.1.3.8 or EC number 3.1.3.26.

The term “a Buttiauxella sp. phytase”, as used herein refers to aphytase protein obtained from a Buttiauxella sp. In one embodiment, theButtiauxella sp. phytase comprises the amino acid sequence derived froma strain deposited under the accession number NCIMB 41248 (NationalCollections of Industrial Marine and Food Bacteria, Scotland, UK). Inone advantageous embodiment, a Buttiauxella sp. phytase comprises theamino acid sequence of SEQ ID NO: 2.

The term “corresponding to a Buttiauxella sp. phytase”, as used herein,refers to an enzyme having one or more of the same or similar functionalcharacteristics or sequence of a Buttiauxella sp. phytase, but notnecessarily obtained from a source of Buttiauxella sp.

The term “Buttiauxella” refers to a genus of gram negative,facultatively anaerobic bacteria of the family Enterobacteriaceae andButtiauxella spp include B. agrestis, B. brennerase, B. ferragutiae, B.gaviniae, B. izardii, B. noackiae, and B. warmboldiae. Strains of theButtiauxella species are available for example from the American TypeCulture Collection (ATCC) and DSMZ, the German National Resource Centrefor Biological Material.

The term “wild-type phytase” or “wild-type” refers to an enzyme with anamino acid sequence found in nature. In particular, the wild-typephytase is that shown as SEQ ID. No. 1.

The term “variant” of Buttiauxella sp. phytase” or “phytase variant” asused herein means a phytase enzyme with an amino acid sequence thatdiffers by at least one amino acid substitution, insertion and/ordeletion as compared with the amino acid sequence of the phytase of SEQ.ID NO: 1. The terms “variant” and “variation” as used herein merelymeans that there is a difference between sequence of the amino acidsequence of the phytase variant and the amino acid sequence of SEQ. IDNO: 1, and does not mean that an amino acid sequence or nucleotidesequence of SEQ. ID NO: 1 or any other phytase served as a startingmaterial in any way and/or was physically varied, mutated, modified orotherwise altered to yield the variant. Simply put, the phytase variantsof this disclosure (including their amino acid and nucleotidessequences), may be prepared by any method, and skilled artisans will bereadily familiar with numerous methods, some of which are describedherein, for making the phytase variants.

The term “protein”, as used herein, includes proteins, polypeptides, andpeptides.

The terms “amino acid residue equivalent to”, “amino acid correspondingto” and grammatical equivalents thereof are used herein to refer to anamino acid residue of a protein having the similar position and effectas that indicated in a particular amino acid sequence of a particularprotein. The person of skill in the art will recognize the equivalenceof specified residues in comparable phytase proteins.

“Percent sequence identity”, with respect to two amino acid orpolynucleotide sequences, refers to the percentage of residues that areidentical in the two sequences when the sequences are optimally aligned.Thus, 80% amino acid sequence identity means that 80% of the amino acidsin two optimally aligned polypeptide sequences are identical. Percentidentity can be determined, for example, by a direct comparison of thesequence information between two molecules by aligning the sequences,counting the exact number of matches between the two aligned sequences,dividing by the length of the shorter sequence, and multiplying theresult by 100. Readily available computer programs can be used to aid inthe analysis, such as ALIGN, Dayhoff, M. O. in “Atlas of ProteinSequence and Structure”, M. O. Dayhoff et., Suppl. 3:353-358, NationalBiomedical Research Foundation, Washington, D.C., which adapts the localhomology algorithm of Smith and Waterman (1981) Advances in Appl. Math.2:482-489 for peptide analysis. Programs for determining nucleotidesequence identity are available in the Wisconsin Sequence AnalysisPackage, Version 8 (available from Genetics Computer Group, Madison,Wis.) for example, the BESTFIT, FASTA and GAP programs, which also relyon the Smith and Waterman algorithm. These programs are readily utilizedwith the default parameters 5 recommended by the manufacturer anddescribed in the Wisconsin Sequence Analysis Package referred to above.An example of an algorithm that is suitable for determining sequencesimilarity is the BLAST algorithm, which is described in Altschul, etal., J. Mol. Biol. 215:403-410 (1990). Software for performing BLASTanalyses is publicly available through the National Center forBiotechnology Information (http://www.ncbi.nlm.nih.gov/) Likewise,computer programs for determining percent homology are also readilyavailable.

The term “property” or grammatical equivalents thereof in the context ofa polypeptide, as used herein, refer to any characteristic or attributeof a polypeptide that can be selected or detected. These propertiesinclude, but are not limited to oxidative stability, substratespecificity, catalytic activity, thermal stability, temperature and/orpH activity profile, feed processing stability, and ability to besecreted.

The term “enhanced stability” in the context of a property such asstability at higher temperatures, lower pH, etc. refers to a higherretained enzyme activity over time as compared to another identifiedphytase such as that of SEQ ID NO: 1. Unless another phytase isspecifically identified, the term “enhanced stability” when used herein,will refer to a higher retained enzyme activity over time as compared tothe phytase of SEQ ID NO: 1.

The terms “thermally stable” and “thermostable” refer to phytases of thepresent disclosure that retain a specified amount of enzymatic activityafter exposure to an elevated temperature. Phytase variants according tothis disclosure are considered thermostable at a specified temperatureif the enzyme retains greater than 50% of its activity after exposure tothe specified temperature for 10 minutes at pH 5.5 in buffer.

The term “improved thermal activity” as it pertains to phytase variantsof the present disclosure means that the phytase variant exhibits thesame or an increased amount of phytase enzyme activity at elevatedtemperature as compared to the phytase enzyme activity of anotheridentified phytase such as that of SEQ ID NO: 1. Unless another phytaseis specifically identified, the term “improved thermal activity” whenused herein will refer to the thermal activity of a phytase variant ofthis disclosure as compared to the thermal activity of the phytase ofSEQ ID NO: 1. Further discussion about thermal activity is providedbelow in Example 6.

The terms “polynucleotide” and “nucleic acid”, used interchangeablyherein, refers to a polymeric form of nucleotides of any length, eitherribonucleotides or deoxyribonucleotides. These terms include, but arenot limited to, a single-, double- or triple-stranded DNA, genomic DNA,cDNA, RNA, DNA-RNA hybrid, or a polymer comprising purine and pyrimidinebases, or other natural, chemically, biochemically modified, non-naturalor derivatized nucleotide bases.

As used herein the term “gene” refers to a polynucleotide (e.g., a DNAsegment), that encodes a polypeptide and includes regions preceding andfollowing the coding regions as well as intervening sequences (introns)between individual coding segments (exons).

As used herein, the terms “DNA construct,” “transforming DNA” and“expression vector” are used interchangeably to refer to DNA used tointroduce sequences into a host cell or organism. The DNA may begenerated in vitro by PCR or any other suitable technique(s) known tothose in the art. The DNA construct, transforming DNA or recombinantexpression cassette can be incorporated into a plasmid, chromosome,mitochondrial DNA, plastid DNA, virus, or nucleic acid fragment.Typically, the recombinant expression cassette portion of an expressionvector, DNA construct or transforming DNA includes, among othersequences, a nucleic acid sequence to be transcribed and a promoter. Inpreferred embodiments, expression vectors have the ability toincorporate and express heterologous DNA fragments in a host cell.

As used herein, the term “vector” refers to a polynucleotide constructdesigned to introduce nucleic acids into one or more cell types. Vectorsinclude cloning vectors, expression vectors, shuttle vectors, plasmids,cassettes and the like.

As used herein in the context of introducing a nucleic acid sequenceinto a cell, the term “introduced” refers to any method suitable fortransferring the nucleic acid sequence into the cell. Such methods forintroduction include but are not limited to protoplast fusion,transfection, transformation, conjugation, and transduction and includesreference to the incorporation of a nucleic acid sequence into aeukaryotic or prokaryotic cell wherein the nucleic acid sequence may beincorporated into the genome of the cell (e.g., chromosome, plasmid,plastid, or mitochondrial DNA), converted into an autonomous replicon,or transiently expressed (e.g., transfected mRNA).

The term “optimal alignment” refers to the alignment giving the highestpercent identity score.

The terms “protein” and “polypeptide” are used interchangeabilityherein. In the present disclosure and claims, the conventionalone-letter and three-letter codes for amino acid residues are used. The3-letter code for amino acids as defined in conformity with the IUPACIUBJoint Commission on Biochemical Nomenclature (JCBN). It is alsounderstood that a polypeptide may be coded for by more than onenucleotide sequence due to the degeneracy of the genetic code.

Variants of this disclosure are described by the following nomenclature:[original amino acid residue of SEQ. ID NO: 1/position of original aminoacid residue in SEQ. ID NO: 1/substituted amino acid residue]. Forexample, in SEQ ID NO: 2, the substitution of threonine (T) for theoriginal alanine (A) in position 89 of SEQ ID NO: 1 is represented asA89T. When a position suitable for substitution is identified hereinwithout a specific amino acid suggested, it is to be understood that anyamino acid residue may be substituted for the amino acid residue presentin the position. Where a variant phytase contains a deletion incomparison with other phytases the deletion is indicated with “*”. Forexample, a deletion at position A89 of SEQ. ID NO: 1 is represented asA89*. A deletion of two or more consecutive amino acids is indicated,for example, as (89-91)*.

The term “signal sequence” or “signal peptide” refers to any sequence ofnucleotides and/or amino acids which may participate in the secretion ofthe mature or precursor forms of the protein. This definition of signalsequence is a functional one, meant to include all those amino acidsequences encoded by the N-terminal portion of the protein gene, whichparticipate in the effectuation of the secretion of protein. They areoften, but not universally, bound to the N-terminal portion of a proteinor to the N-terminal portion of a precursor protein.

“Host strain” or “host cell” refers to a suitable host for an expressionvector comprising DNA according to the present disclosure.

The terms “derived from” and “obtained from” refer to not only a phytaseproduced or producible by a strain of the organism in question, but alsoa phytase encoded by a DNA sequence isolated from such strain andproduced in a host organism containing such DNA sequence. Additionally,the terms refers to a phytase which is encoded by a DNA sequence ofsynthetic and/or cDNA origin and which has the identifyingcharacteristics of the phytase in question. Hence, a phytase that is“derived from” and “obtained from” another phytase does not necessarilymean that the phytase has been physically derived or physically obtainedfrom the second phytase, but rather can also mean that the phytase inquestion has been prepared using knowledge or ideas derived fromknowledge of the second phytase.

By “functional fragment” is meant a fragment of the polypeptide thatretains that characteristic properties of that polypeptide. In thecontext of the present invention, a functional fragment of a phytaseenzyme is a fragment that retains the phytase cleavage capability of thewhole protein.

The term “isolated”, “recovered” or “purified” refers to a material thatis removed from its original environment. The term “substantiallypurified” means that the material has been purified to at least asubstantial degree.

In one aspect, preferably the nucleotide or amino acid sequence is in anisolated form. The term “isolated” means that the sequence is at leastsubstantially free from at least one other component with which thesequence is naturally associated in nature and as found in nature.

In one aspect, preferably the nucleotide or amino acid sequence is in apurified form. The term “purified” means that the sequence is in arelatively pure state at least 1%, 5% pure or 10% pure, more preferablyat least 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% pure. In a preferredembodiment, when referring to a polypeptide, the purity as defined aboveis determined in terms of being purified from other polypeptides bySDS-PAGE electrophoresis. In a preferred embodiment, when referring to apolynucleotide, the purity as defined above is determined in terms ofbeing purified from other polynucleotides.

As used with reference to the present invention, the terms “expression”,“expresses”, “expressed” and “expressable” are synonymous with therespective terms “transcription”, “transcribes”, “transcribed” and“transcribable”.

As used with reference to the present invention, the terms“transformation” and “transfection” refer to a method of introducingnucleic acid sequences into hosts, host cells, tissues or organs.

As used with reference to the present invention, the terms “produce”,“producing”, “produced”, “produceable”, “production” are synonymous withthe respective terms “prepare”, “preparing”, “prepared”, “preparation”,“generated”, “generation” and “preparable”.

A “feed” and a “food,” respectively, means any natural or artificialdiet, meal or the like or components of such meals intended or suitablefor being eaten, taken in, digested, by an animal (feed) and a humanbeing (food), respectively.

A “food or feed additive” is a compound or a multi component compositionintended for or suitable for being added to food or feed. It may, but isnot required to, comprise one or more compounds such as vitamins,minerals or feed enhancing enzymes and suitable carriers and/orexcipients, and it is usually provided in a form that is suitable forbeing added to animal feed.

The term “starch liquefaction” refers to a process by which starch isconverted to shorter chain and less viscous dextrins.

The term “substrate” refers to a substance that is or comprises at leastone entity that can be acted on by the enzyme(s) of the presentinvention. Examples of such entities include: phytate, and intermediateproducts of phytate degradation such as inositol pentaphosphates,tetraphosphates, triphosphates diphosphates, and monophosphates.Examples of substrates that comprise said entity include grains, cerealsand other plant materials or carbohydrate-based materials for use in,for example, ingredients for feeds, liquefaction, saccharification,fermentation, simultaneous saccharification/fermentation and/or singlestep process for production of, for example, fermentation alcohols(e.g., ethanol or butanol) or sugars for use in fermentations for theproduction of alcohols (e.g., ethanol or butanol) or sugars for makingother products (e.g., non-alcohol products).

The term “alcohol fermentations” refers to fermentative processes inwhich a microorganism (e.g., a yeast) converts a substrate into ametabolite which is classified as an alcohol (e.g., ethanol or butanol).

A “promoter” is a regulatory sequence that is involved in binding RNApolymerase to initiate transcription of a gene.

“Under transcriptional control” is a term well understood in the art toindicates that transcription of a polynucleotide sequence, usually a DNAsequence, depends on its being operably linked to an element whichcontributes to the initiation of, or promotes transcription.

“Under translational control” is a term well understood in the art thatindicates a regulatory process that occurs after mRNA has been formed.

As used herein when describing proteins and genes that encode them, theterm for the gene is italicized, (e.g., the gene that encodesButtiauxella phytase). The term for the protein is generally notitalicized and the first letter is generally capitalized.

The term “operably linked” refers to juxtaposition wherein the elementsare in an arrangement allowing them to be functionally related. Forexample, a promoter is operably linked to a coding sequence if itcontrols the transcription of the sequence.

The term “selective marker” refers to a gene capable of expression in ahost that allows for ease of selection of those hosts containing anintroduced nucleic acid or vector. Examples of selectable markersinclude but are not limited to antimicrobials (e.g., hygromycin,bleomycin, or chloramphenicol) and/or genes that confer a metabolicadvantage, such as a nutritional advantage on the host cell.

The term “heterologous” with reference to a polynucleotide or proteinrefers to a polynucleotide or protein that does not naturally occur in ahost cell.

The term “endogenous” with reference to a polynucleotide or proteinrefers to a polynucleotide or protein that occurs naturally in the hostcell.

The terms “recovered”, “isolated”, and “separated” as used herein referto a compound, protein, cell, nucleic acid or amino acid that is removedfrom at least one component with which it is naturally associated.

As used herein, the terms “transformed”, “stably transformed” and“transgenic” used in reference to a cell means the cell has a non-native(e.g., heterologous) nucleic acid sequence integrated into its genome oras an episomal plasmid that is maintained through multiple generations.

As used herein, the term “expression” refers to the process by which apolypeptide is produced based on the nucleic acid sequence of a gene.The process includes both transcription and translation.

Although any methods and materials similar or equivalent to thosedescribed herein can be used in the practice or testing of the presentdisclosure, exemplary and advantageous methods and materials are nowdescribed. All publications mentioned herein are incorporated herein byreference to the extent necessary to disclose and describe the methodsand/or materials connected with the disclosure for which thepublications are cited.

Other definitions of terms may appear throughout the specification.Before the exemplary embodiments are described in more detail, it is tounderstand that this disclosure is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present disclosure will be limited only by the appendedclaims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassedwithin this disclosure. The upper and lower limits of these smallerranges may independently be included or excluded in the range, and eachrange where either, neither or both limits are included in the smallerranges is also encompassed within this disclosure, subject to anyspecifically excluded limit in the stated range. Where the stated rangeincludes one or both of the limits, ranges excluding either or both ofthose included limits are also included in this disclosure.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. Thus, for example, reference to “agene” includes a plurality of such candidate agents and reference to“the cell” includes reference to one or more cells and equivalentsthereof known to those skilled in the art, and so forth.

The publications discussed herein are provided solely for theirdisclosure prior to the filing date of the present application. Nothingherein is to be construed as an admission that such publicationsconstitute prior art to the claims appended hereto.

Phytase enzymes used as parent or precursor enzymes include aButtiauxella sp. phytase and those enzymes corresponding to aButtiauxella sp. phytase. In some embodiments, the parent Buttiauxellasp. phytase comprises the amino acid sequence derived from aButtiauxella sp. strain deposited under the accession number NCIMB41248. In some embodiments, the parent Buttiauxella sp. phytasecomprises the amino acid sequence of SEQ ID NO: 1. In some embodiments,the parent Buttiauxella sp. phytase is derived from B. agrestis, B.brennerase, B. ferragutiae, B. gaviniae, B. izardii, B. noackiae, and B.warmboldiae. Reference is made to WO 2006/043178, which is specificallyincorporated herein by reference and which describes phytases obtainablefrom or derived from a parent Buttiauxella sp. and phytasescorresponding to a Buttiauxella sp. phytase enzyme. In some embodiments,a wild-type Buttiauxella sp. Phytase variant has at least 50%, at least60%, at least 75%, at least 80%, at least 85%, at least 90%, at least93%, at least 95%, at least 96%, at least 97%, at least 98%, and atleast 99% amino acid sequence identity to the polypeptide of SEQ ID NO:1.

Embodiments of the present disclosure are concerned with variantphytases (e.g., variant Buttiauxella sp. phytases). Specifically, WO2006/043178 describes the mutagenesis of a wild-type phytase enzymehaving the sequence disclosed therein as SEQ ID NO: 3. A number ofpreferred mutations are taught in WO 2006/043178. A variant phytase willcontain at least one amino acid substitution, deletion or insertion,with amino acid substitutions often being advantageous. The amino acidsubstitution, insertion or deletion may occur at any residue within thephytase peptide. A phytase variant of the present disclosure is avariant which does not have an amino acid sequence identical to theamino acid sequence of SEQ ID NO: 1 herein.

In advantageous embodiments of the present disclosure, the variant willcomprise a substitution in a Buttiauxella sp. phytase and morespecifically corresponding to said equivalent positions in SEQ ID NO: 1.In some embodiments, the substitution comprises any of the remaining 19amino acids corresponding to A, C, D, E, F, 0, H, I, K, L, M, N, P, Q,R, S, T, V, W or Y. However, also synthetic and other amino acids couldbe used.

Variants may be prepared by random mutagenesis, site saturationmutagenesis, and site specific mutagenesis of nucleotides in the DNAencoding the phytase protein, using cassette or PCR mutagenesis or othertechniques well known in the art, to produce variants, which maythereafter be produced in cell culture. Reference is made to Morinaga etal., (1984) Biotechnology 2: 646-649; Nelson and Long, (1989) AnalyticalBiochem., 180: 147-151 and Sarkar and Sommer (1999) Biotechniques 8:404-407. Variant phytase protein fragments may also be prepared by invitro synthesis using established techniques.

Polynucleotides may be obtained by standard procedures known in the artfrom, for example, cloned DNA (e.g., a DNA “library”), by chemicalsynthesis, by cDNA cloning, by PCR (U.S. Pat. No. 4,683,202 or Saiki etal., Science 239:487-491 (1988)), by synthetically established methods(Beucage et al., (1981) Tetrahedron Letters 22: 1859-1869 and Matthes etal, EMBO J. 3:801-895 (1984)) or by the cloning of genomic DNA, orfragments thereof, substantially purified from a desired cell, such as aButtiauxella sp. (see, for example, Sambrook et al., 2001, MolecularCloning, A Laboratory Manual, 3d Ed., Cold Spring Harbor LaboratoryPress, Cold Spring Harbor, N.Y.; Glover, D M and Hames, B D (Eds.),1995, DNA Cloning 1: A Practical Approach and DNA Cloning 2: A PracticalApproach, Oxford University Press, Oxford). Nucleic acid sequencesderived from genomic DNA, and derivatives thereof, may containregulatory regions in addition to coding regions.

To express the polypeptides standard recombinant DNA expression methodscan be used (see, for example, Goeddel; Gene Expression Technology.Methods in Enzymology 185, Academic Press, San Diego, Calif. (1990)).For example, DNA encoding the desired polypeptide can be inserted intoan expression vector which is then transfected into a suitable hostcell. It is understood that the design of the expression vector,including the selection of regulatory sequences is affected by factorssuch as the choice of the host cell, the level of expression of proteindesired and whether expression is constitutive or inducible.

Transfection of the expression vector into a host cell can be carriedout using standard techniques such as electroporation, calcium-phosphateprecipitation, and DEAE-dextran transfection.

Suitable host cells for cloning or expressing the DNA in the vectorsherein are the prokaryote, yeast, or higher eukaryote cells like plantcells as described above. In addition to prokaryotes, eukaryoticmicrobes such as filamentous fungi or yeast are suitable cloning orexpression hosts for the phytase variants according to this disclosure.

Host cells can be transformed with the above-described expression orcloning vectors for protein production and cultured in conventionalnutrient media modified as appropriate for inducing promoters, selectingtransformants, or amplifying the genes encoding the desired sequences.The culture conditions, such as temperature, pH, and the like, are thosepreviously used with the host cell selected for expression, and will beapparent to the ordinarily skilled artisan.

The polypeptide prepared from the cells can be purified using, forexample, hydroxylapatite chromatography, gel electrophoresis, dialysis,and affinity chromatography.

In some embodiments, a variant phytase according to this disclosure willhave altered properties. Advantageously, a variant according toembodiments of this disclosure will have improved properties as comparedto the wild type phytase of SEQ. ID NO: 1. In some embodiments, thealtered, e.g., improved properties will be thermal stability, thermalactivity, feed processing stability and/or specific activity (see FIG.2).

In some embodiments, variants encompassed by this disclosure will haveincreased thermal stability as compared to Buttiauxella sp. phytasesknown in the art (e.g., Buttiauxella sp. phytases according to SEQ IDNO: 1). In some embodiments, the variant will have a thermal stabilitydifference (TD) of at least 21.9° C., at least 22.4° C., at least 22.6°C., at least 22.9° C., at least 23.2° C., at least 23.4° C., at least23.5° C., at least 23.5° C., at least 23.7° C., at least 24.1° C., atleast 24.2° C., at least 24.4° C., at least 24.9° C., at least 25.0° C.,at least 25.9° C., at least 26.5° C. and at least 26.8° C. compared toBP-WT.

In some embodiments, variants encompassed by this disclosure willexhibit increased stability at elevated temperatures as compared to thewild type phytase of SEQ. ID NO: 1. In some embodiments, the phytasevariant will be thermostable at about 65° C., at about 70° C., at about75° C., at about 80° C. or higher. As discussed above, phytasesaccording to this disclosure are considered thermo stable if the enzymeretains greater than 50% of its activity after exposure to a specifiedtemperature for 10 minutes at pH 5.5.

In some embodiments, variants will have a higher thermal activity. Insome embodiments, the variant encompassed by this disclosure will have athermal activity difference (TAD) of at least 17.4° C., at least 17.5°C., at least 17.6° C., at least 17.8° C., at least 17.9° C., at least18.4° C., at least 18.7° C., at least 18.8° C., at least 18.9° C., atleast 19.0° C., at least 19.3° C., at least 19.5° C., at least 20.0° C.,at least 20.1° C. and at least 20.2° C. compared to BP-WT.

In some embodiments, variant phytases according to this disclosure willhave a specific activity of at least 1000 U/mg, at least 1200 U/mg, atleast 1400 U/mg, at least 1600 U/mg, at least 1800 U/mg, at least 2000U/mg, at least 2200 U/mg, at least 2300 U/mg, at least 2400 U/mg and atleast 2500 U/mg, wherein the specific activity is determined byincubating the phytase at 67° C. in a solution containing 10 mM phytase,1 mM CaCl₂ in 200 mM sodium acetate buffer at pH 5.5 as detailed inExample 3 of the present disclosure.

In some embodiments, variant phytases according to this disclosure willhave a specific activity of at least 800 U/mg, at least 1000 U/mg, atleast 1200 U/mg, at least 1400 U/mg, at least 1600 U/mg, at least 1800U/mg, at least 2000 U/mg, at least 2200 U/mg, at least 2300 U/mg, atleast 2400 U/mg, at least 2500 U/mg and at least 2600 U/mg, wherein thespecific activity is determined by incubating the phytase at 80° C. in asolution containing 10 mM phytate, 1 mM CaCl₂ in 200 mM sodium acetatebuffer at pH 5.5 as detailed in example 3 of the present disclosure.

In some embodiments, variant phytases according to this disclosure willbe thermostable at 80° C., i.e. retain 50% of activity after exposure to80° C. for 10 minutes at pH 5.5 and at the same time have a specificactivity of at least 2500 U/mg at 80° C. and at least 2300 U/mg at 67°C., wherein the specific activity is determined by incubating thephytase at the specified temperature in a solution containing 10 mMphytate, 1 mM CaCl₂ in 200 mM sodium acetate buffer at pH 5.5 asdetailed in example 3 of the present disclosure.

In some embodiments, variants encompassed by this disclosure may be usedin a method of producing a phosphate compound comprising treating aphytate with a variant phytase encompassed by this disclosure (e.g.,variant of SEQ ID NO: 2). The phytate may be myo-inositol di-, tri-,tetra, and/or pentaphosphates. Other suitable organic phosphates includeinositol-tetraphosphates and inositol-oligophosphates.

In some embodiments, variants encompassed by this disclosure will retainessentially the same level of specific activity as BP-WT but have anincrease in stability at higher temperatures, higher pH, and/or lower pHas compared to BP-WT.

In some embodiments, variants encompassed by this disclosure will retainessentially the same level of specific activity as BP-WT but have animproved thermal activity.

In some embodiments, this disclosure provides a method of producing anenzyme having phytase activity as described herein, comprising: (a)providing a host cell transformed with an expression vector comprising apolynucleotide encoding a phytase variant as described herein, (b)cultivating the transformed host cell under conditions suitable for thehost cell to produce the phytase variant; and (c) recovering the phytasevariant.

In some embodiments, the expression vector will comprise apolynucleotide which encodes a phytase comprising an amino acid sequencehaving a substitution in amino acid residues corresponding to positionsshown in FIG. 2.

In some embodiments of this disclosure, the host strain is geneticallyengineered to express heterologous phytases or variants having phytaseactivity according to this disclosure.

Host cells useful for the production of a phytase encompassed by thisdisclosure include bacterial cells, fungal cells and plant cells. Hostcells include both the cells and progeny of the cells and protoplastscreated from the cells which may be used to produce a variant phytaseaccording to this disclosure.

Useful vectors including DNA constructs comprising a polynucleotideencoding a phytase of this disclosure and transformation methods of hostcells are well known in the art and standard techniques and methodologymay be used.

According to this disclosure, a DNA construct comprising nucleic acidencoding a variant phytase encompassed by this disclosure is constructedto transfer and/or express the variant in a host cell. In oneembodiment, the DNA construct is transferred to a host cell by anexpression vector which comprises regulatory sequences (e.g. promoters,ribosomal binding sites, transcriptional start and stop sequences,translational start and stop sequences, enhancers, IS activatorsequences, cell specific expression sequences, signal sequences, and/orterminators) operably linked to the variant phytase coding sequence.

An expression vector comprising a DNA construct with a polynucleotideencoding variant phytase can be any vector which is capable ofreplicating autonomously in a given fungal host organism or ofintegrating into the DNA of the host. In some embodiments, theexpression vector is a plasmid or a bacteriophage. In some embodiments,the expression vector is preassembled and contains sequences requiredfor high-level transcription and a selectable marker. In someembodiments, the coding region for variant phytase gene or part thereofis inserted into this general-purpose expression vector such that it isunder the transcriptional control of the expression construct promoterand terminator sequences. In some embodiments, genes or part thereof areinserted downstream of the strong cbh1 promoter.

Briefly with respect to production of a phytase in fungal host cellsreference in made to Sambrook et al., (1989) supra, Ausubel (1987)supra, van den Hondel et al. (1991) in Bennett and Lasure (Eds.) MOREGENE MANIPULATIONS IN FUNGI, Academic Press (1991) pp. 70-76 and396-428; Nunberg et al., (1984) Mol. Cell Biol. 4:2306-2315; Boel etal., (1984) 30 EMBO J. 3:1581-1585; Finkelstein in BIOTECHNOLOGY OFFILAMENTOUS FUNGI, Finkelstein et al. Eds. Butterworth-Heinemann,Boston, Mass. (1992), Chap. 6; Kinghorn et al. (1992) APPLIED MOLECULARGENETICS OF FILAMENTOUS FUNGI, Blackie Academic and Professional,Chapman and Hall, London; Kelley et al., (1985) EMBO J. 4:475-479;Penttila et al., (1987) Gene 61: 155-164; and U.S. Pat. No. 5,874,276. Alist of suitable vectors may be found in the Fungal Genetics StockCenter Catalogue of Strains (FGSC, www at fgsc.net). Suitable vectorsinclude those obtained from for example Invitrogen Life Technologies andPromega. Specific vectors suitable for use in fungal host cells includevectors such as pFB6, pBR322, pUC 18, pUC100, pDON™201, pDONR™221,pENTR™, pGEM®3Z and pGEM®4Z.

In some embodiments, the vector can be any vector which, when introducedinto a fungal host cell, is integrated into the host cell genome and isreplicated. Some non-limiting examples of such vectors is provided inthe Fungal Genetics Stock Center Catalogue of Strains (FGSC,<www.fgsc.net>>), Additional examples of suitable expression and/orintegration vectors are provided in Sambrook et al., (1989) supra,Ausubel (1987) supra, van den Hondel et al. (1991) in Bennett and Lasure(Eds.) MORE GENE MANIPULATIONS IN FUNGI, Academic Press. 396-428 andU.S. Pat. No. 5,874,276. Particularly useful vectors include pTREX,pFB6, pBR322, PUCI8, pUCI00 and pENTR/D. Suitable plasmids for use inbacterial cells include pBR322 and pUC19 permitting replication in E.coli and pE194 for example permitting replication in Bacillus.

In some embodiments, nucleic acids encoding variant phytase encompassedby this disclosure are operably linked to a suitable promoter, whichshows transcriptional activity in the host cell. In general, theexpression of the variant phytase is accomplished under any suitablepromoter known or later discovered in the art. In some embodiments, thevariant phytase is expressed under a promoter native to the host. Insome embodiments, the phytase variant is expressed under a heterologouspromoter that is active in the host cell. For example, if a Trichodermacell is used as the host cell, then advantageously the promoter isactive in a Trichoderma host cell.

In some embodiments, the promoter is a constitutive or induciblepromoter. A “constitutive promoter” is a promoter that is active undermost environmental and developmental conditions. An “inducible” or“repressible” promoter is a promoter that is active under environmentalor developmental regulation. In some embodiments, promoters areinducible or repressible due to changes in environmental factorsincluding but not limited to, carbon, nitrogen or other nutrientavailability, temperature, pH, osmolarity, the presence of heavymetal(s), the concentration of inhibitor(s), stress, or a combination ofthe foregoing, as is known in the art. In some embodiments, theinducible or repressible promoters are inducible or repressible bymetabolic factors, such as the level of certain carbon sources, thelevel of certain energy sources, the level of certain catabolites, or acombination of the foregoing as is known in the art. In one embodiment,the promoter is one that is native to the host cell. For example, whenT. reesei is the host, the promoter is a native T. reesei promoter suchas the cbh1 promoter which is deposited in GenBank under AccessionNumber D86235.

Suitable non-limiting examples of promoters include cbh1, cbh2, egl1,egl2, egl3, egl4, egl5, xyn1, and xyn2, repressible acid phosphatasegene (phoA) promoter of P. chrysogenus (see e.g., Graessle et al.,(1997) Appl. Environ. Microbiol., 63: 753-756), glucose repressible PCK1promoter (see e.g., Leuker et al., (1997), Gene, 192:235-240),maltoseinducible, glucose-repressible MET3 promoter (see Liu et al.,(2006), Eukary. Cell, 5:638-649), pKi promoter and cpcl promoter. Otherexamples of useful promoters include promoters from A. awamori and A.niger glucoamylase genes (see e.g., Nunberg et al., (1984) Mol. CellBiol. 15 4:2306-2315 and Boel et al., (1984) EMBO J. 3:1581-1585). Also,the promoters of the T. reesei xln1 gene may be useful (see e.g., EPA137280A1).

In some embodiments, the expression vector also includes a transcriptiontermination sequence downstream of the structural gene to provide forefficient termination. In some embodiments, the termination sequence andthe promoter sequence are derived from the same source. In otherembodiments, the termination sequence is homologous to the host cell. Aparticularly suitable terminator sequence is cbh1 derived from aTrichoderma strain and particularly T. reesei. Other useful fungalterminators include the terminator from A. niger or A. awamoriglucoamylase gene (see e.g., Nunberg et al. (1984) supra, and Boel etal., (1984) supra).

Methods used to ligate the DNA construct comprising a polynucleotideencoding the phytase variant, a promoter, a terminator and othersequences and to insert them into a suitable vector are well known inthe art. Linking is generally accomplished by ligation at convenientrestriction sites. If such sites do not exist, the syntheticoligonucleotide linkers are used in accordance with conventionalpractice (see, e.g., Sambrook (1989) supra, and Bennett and Lasure, MOREGENE MANIPULATIONS IN FUNGI, Academic Press, San Diego (1991) pp70-76.). Additionally, vectors can be constructed using knownrecombination techniques (e.g., Invitrogen Life Technologies, GatewayTechnology). Transformation, expression and culture of host cells.

Introduction of a DNA construct or vector into a host cell includestechniques such as transformation; electroporation; nuclearmicroinjection; transduction; transfection, (e.g., lipofection mediatedand DEAE-Dextrin mediated transfection); incubation with calciumphosphate DNA precipitate; high velocity bombardment with DNA-coatedmicroprojectiles; and protoplast fusion.

Transformation methods for Aspergillus and Trichoderma are described in,for example, Yelton et al. (1984) Proc. Natl. Acad. Sci. USA 81:1470-1474; Berka et al., (1991) in Applications of Enzyme Biotechnology,Eds. Kelly and Baldwin, Plenum Press (NY); Cao et al., (2000) Sci.9:991-1001; Campbell et al., (1989) Curro Genet. 16:53-56; Pentilla etal., (1987) Gene 61:155-164); de Groot et al., (1998) Nat. Biotechnol.16:839-842; U.S. Pat. No. 6,022,725; U.S. Pat. No. 6,268,328 and EP 238023. The expression of heterologous protein in Trichoderma is describedin U.S. Pat. No. 6,022,725; U.S. Pat. No. 6,268,328; Harkki et ale(1991); Enzyme Microb. Technol. 13:227-233; Harkki et al., (1989) BioTechnol. 7:596-603; EP 244,234; EP 215,594; and Nevalainen et al., “TheMolecular Biology of Trichoderma and its Application to the Expressionof Both Homologous and Heterologous Genes”, in MOLECULAR INDUSTRIALMYCOLOGY, Eds. Leong and Berka, Marcel Dekker Inc., NY (1992) pp.129-148). Reference is also made to WO96100787 and Bajar et al., (1991)Proc. Natl. Acad. Sci. USA 88:8202-28212 for transformation of Fusariumstrains.

Methods for making DNA constructs useful in transformation of plants andmethods for plant transformation are also known. Some of these methodsinclude Agrobacterium tumefaciens mediated gene transfer;microprojectile bombardment, PEG mediated transformation of protoplasts,electroporation and the like. Reference is made to, for example, U.S.Pat. No. 5,780,708; U.S. Pat. No. 6,803,499; U.S. Pat. No. 6,777,589;Fromm et al. (1990) Biotechnol. 8:833-839; Potrykus et al. (1985) Mol.Gen. Genet. 199:169-177; Brisson et al., (1984) Nature 310:511514;Takamatsu et al., (1987) EMBO J 6:307-311; Coruzzi et al., (1984) EMBO J3:1671-1680; Broglie et al. (1984) Science 224:838-843; Winter J andSinibaldi R M (1991) Results Probl Cell Differ 17:85-105; Hobbs S orMurry L E (1992) in McGraw Hill Yearbook of Science and Technology,McGraw Hill, New York, N.Y., pp 191-196; and Weissbach and Weissbach(1988) Methods for Plant Molecular Biology, Academic Press, New York,N.Y., pp 421-463. Transformed cells may be cultured using standardtechniques under suitable conditions in shake flask cultivation, smallscale or large scale fermentations (including continuous, batch and fedbatch fermentations) in laboratory or industrial fermentors, withsuitable medium containing physiological salts and nutrients (See, e.g.,Pourquie, J. et al., BIOCHEMISTRY AND GENETICS OF CELLULOSE DEGRADATION,eds. Aubert, J. P. et al., Academic Press, pp. 71-86, 1988 and Ilmen, M.et al., (1997) Appl. Environ. Microbiol. 63: 1298-1306). Commoncommercially prepared media (e.g., Yeast Malt Extract (YM) broth, LuriaBertani (LB) broth and Sabouraud Dextrose (SD) broth find use in thepresent disclosure. Preferred culture conditions for filamentous fungalcells are known in the art and may be found in the scientific literatureand/or from the source of the fungi such as the American Type CultureCollection and Fungal Genetics Stock Center.

In some embodiments, genetically stable transformants are constructedwith vector systems whereby the nucleic acid encoding a phytase variantis stably integrated into a host strain chromosome. Transformants arethen purified by known techniques.

In order to evaluate the expression of phytase variants having phytaseactivity by a cell line that has been transformed with a heterologouspolynucleotide encoding a phytase variant having phytase activityencompassed by this disclosure, assays can be carried out at the proteinlevel, the RNA level or by use of functional bioassays particular tophytase activity and/or production. In general assays employed include,Northern blotting, dot blotting (DNA or RNA analysis), RT-PCR (reversetranscriptase polymerase chain reaction), or in situ hybridization,using an appropriately labelled probe (based on the nucleic acid codingsequence) and conventional Southern blotting and autoradiography.

In addition, the production and/or expression of a phytase varianthaving phytase activity may be measured in a sample directly, forexample, by assays directly measuring phytase activity (FTU) by therelease of inorganic phosphate. The inorganic phosphate forms a yellowcomplex with acidic vanadate-molybdate reagent and the yellow complexwas measured at a wavelength of 415 nm in a spectrophometer and thereleased inorganic phosphate was quantified with a phosphate standardcurve. One unit of phytase (FTU) is the amount of enzyme that releases 1micromole of inorganic phosphate (Pi) from phytate per minute.

In addition, gene expression, may be evaluated by immunological methods,such as immunohistochemical staining of cells, tissue sections orimmunoassay of tissue culture medium, e.g., by Western blot or ELISA.Such immunoassays can be used to qualitatively and quantitativelyevaluate expression of a phytase. The details of such methods are knownto those of skill in the art and many reagents for practicing suchmethods are commercially available.

Assays for phytase activity are well known in the art and one example isthe classic assay for liberation of inorganic phosphate developed byFiske and SubbaRow, Journal of Biological Chemistry 66:375-392 (1925). Avariation of this method is found in Mitchell et al., Microbiol.143:245-252 (1997). An alternative method is described in FOOD CHEMICALSCODEX, 4th Edition, Committee on Food Chemicals Codex, Institute ofMedicine, National Academy Press, Washington, D.C., 1996 at pages809-810. Each of these references is incorporated herein. In a number ofthese assays colorimetry is then performed using a spectrophotometer andcompared to controls of known concentration of inorganic phosphate (Pi)and/or controls produced by reactions with enzymes having known phytaseactivity. A Unit of activity is determined as the amount of enzymesample required to liberate 1 μmol Pi per minute from phytate underdefined reaction conditions. Reference is also made to U.S. Pat. No.6,221,644 and U.S. Pat. No. 6,139,902.

In some embodiments of this disclosure, the phytase variants havingphytase activity expressed by a Trichoderma or Aspergillus host will begreater than 1 gram protein per liter (g/l), greater than 2 g/l, greaterthan 5 g/l, greater than 10 g/l, greater than 20 g/l, greater than 25g/l, greater than 30 g/l, greater than 50 g/l and also greater than 100g/l of culture media.

The polypeptides produced upon expression of the nucleic acid sequencesof this disclosure can be recovered or isolated from the fermentation ofcell cultures and substantially purified in a variety of ways accordingto well established techniques in the art. One of skill in the art iscapable of selecting the most appropriate isolation and purificationtechniques. The phytase of this disclosure can be recovered from culturemedium or from host cell lysates. If membrane-bound, it can be releasedfrom the membrane using a suitable detergent solution (e.g. Triton-X100) or by enzymatic cleavage. Cells employed in expression of phytasecan be disrupted by various physical or chemical means, such asfreeze-thaw cycling, sonication, mechanical disruption, or cell lysingagents. It may be desired to purify the phytase from recombinant cellproteins or polypeptides. The following procedures are exemplary ofsuitable purification procedures: by fractionation on an ion-exchangecolumn; ethanol precipitation; reverse phase HPLC; chromatography onsilica or on a cation-exchange resin such as DEAE; chromatofocusing;SDS-PAGE; ammonium sulfate precipitation; gel filtration using, forexample, Sephadex G-75; protein A Sepharose columns to removecontaminants; and metal chelating columns to bind epitope-tagged formsof the phytase. Various methods of protein purification may be employedand such methods are known in the art and described for example inDeutscher, METHODS IN ENZYMOLOGY, 182 (1990); Scopes, PROTEINPURIFICATION: PRINCIPLES AND PRACTICE, Springer-Verlag, New York (1982).The purification step(s) selected will depend, for example, on thenature of the production process used and the particular form of phytaseproduced.

In general, a phytase or phytase variant (including the phytaseaccording to SEQ ID NO: 1) produced in cell culture is secreted into themedium and may be purified or isolated, e.g., by removing unwantedcomponents from the cell culture medium. In some cases, the phytasevariant can be produced in a cellular form necessitating recovery from acell lysate. In such cases the enzyme is purified from the cells inwhich it was produced using techniques routinely employed by those ofskill in the art. Examples include, but are not limited to, affinitychromatography (see e.g., Tilbeurgh et al., (1984) FEBS Lett. 16:215);ion-exchange chromatographic methods (see e.g. Goyal et al., (1991)Biores. Technol. 36:37; Fliess et al., (1983) Eur. J Appl. Microbiol.Biotechnol. 17:314; Bhikhabhai et al. (1984) J Appl. Biochem. 6:336; andEllouz et al., (1987) Chromatography 396:307), including ion-exchangeusing materials with high resolution power (see e.g., Medve et al.,(1998) J Chromatography A 808: 153); hydrophobic interactionchromatography (see e.g., Tomaz and Queiroz, (1999) J Chromatography A865: 123); two-phase partitioning (see e.g., Brumbauer, et al., (1999)Bioseparation 7:287); ethanol precipitation; reverse phase HPLC;chromatography on silica or on a cation-exchange resin such as DEAE;chromatofocusing; SDS-PAGE; ammonium sulphate precipitation; and/or gelfiltration using, e.g., Sephadex G-75.

In some embodiments of the present disclosure, fungal cells expressing aheterologous phytase variants are grown under batch or continuousfermentation conditions. A classical batch fermentation is a closedsystem, wherein the composition of the medium is set at the beginning ofthe fermentation and is not subject to artificial alterations during thefermentation. Thus, at the beginning of the fermentation the medium isinoculated with the desired organism(s). In this method, fermentation ispermitted to occur without the addition of any components to the system.Typically, a batch fermentation qualifies as a “batch” with respect tothe addition of the carbon source and attempts are often made atcontrolling factors such as pH and oxygen concentration. The metaboliteand biomass compositions of the batch system change constantly up to thetime the fermentation is stopped. Within batch cultures, cells progressthrough a static lag phase to a high growth log phase and finally to astationary phase where growth rate is diminished or halted. Ifuntreated, cells in the stationary phase eventually die. In general,cells in log phase are responsible for the bulk of production of endproduct.

A variation on the standard batch system is the “fed-batch fermentation”system, which also finds use with the present disclosure. In thisvariation of a typical batch system, the substrate is added inincrements as the fermentation progresses. Fed-batch systems are usefulwhen catabolite repression is apt to inhibit the metabolism of the cellsand where it is desirable to have limited amounts of substrate in themedium. Measurement of the actual substrate concentration in fed-batchsystems is difficult and is therefore estimated on the basis of thechanges of measurable factors such as pH, dissolved oxygen and thepartial pressure of waste gases such as CO₂. Batch and fed-batchfermentations are common and well known in the art.

Continuous fermentation is an open system where a defined fermentationmedium is added continuously to a bioreactor and an equal amount ofconditioned medium is removed simultaneously for processing. Continuousfermentation generally maintains the cultures at a constant high densitywhere cells are primarily in log phase growth.

Continuous fermentation allows for the modulation of one factor or anynumber of factors that affect cell growth and/or end productconcentration. For example, in one embodiment, a limiting nutrient suchas the carbon source or nitrogen source is maintained at a fixed rate anall other parameters are allowed to moderate. In other systems, a numberof factors affecting growth can be altered continuously while the cellconcentration, measured by media turbidity, is kept constant. Continuoussystems strive to maintain steady state growth conditions. Thus, cellloss due to medium being drawn off must be balanced against the cellgrowth rate in the fermentation. Methods of modulating nutrients andgrowth factors for continuous fermentation processes as well astechniques for maximizing the rate of product formation are well knownin the art of industrial microbiology.

In an embodiment of this disclosure, an enzyme composition is providedcomprising at least one phytase in accordance with this disclosure.Compositions according to this disclosure may be prepared in accordancewith methods known in the art and may be in the form of a liquid or adry composition.

Liquid compositions need not contain anything more than the phytaseenzyme, which typically may be in either a substantially purified or atleast partially purified form, although a substantially purified formoften will be advantageous. A stabilizer such as glycerol, sorbitol ormono propylene glycol often may be added. The liquid composition mayalso comprise one or more other additives, such as salts, sugars,preservatives, pH-adjusting agents (i.e., buffering agents), proteins,or phytate (a phytase substrate). Typical liquid compositions areaqueous or oil-based slurries.

Dry compositions may be spray-dried compositions, in which case thecomposition need not contain anything more than the enzyme in a dryform. Usually, however, dry compositions are so-called granulates whichmay readily be mixed with for example food or feed components, or morepreferably, form a component of a pre-mix. The particle size of theenzyme granulates preferably is compatible with that of the othercomponents of the mixture.

In some embodiments, an enzyme composition including a variant phytaseencompassed by this disclosure will be optionally used in combinationwith anyone or combination of the following enzymes—glucoamylases, alphaamylases, proteases, pullulanases, isoamylases, cellulases,hemicellulases, xylanases, cyclodextrin glycotransferases, lipases,phytases, laccases, oxidases, esterases, cutinases, pectinases, glucoseoxidases, beta glucosidases, phosphatases, beta-amylase, hydrolases,transferases other phytases and combinations thereof.

In some embodiments, the phytase composition is a food or animal feedcomposition. A food or animal feed composition may comprise a phytase ata concentration of 10 to 15,000 U/kg feed or food (e.g. 100 to 5,000U/kg, 200-2,000 U/kg and also 500-1000 U/kg). The phytase compositionmay be used as an additive which is active in the digestive tract, oflivestock and domestic animals such as poultry, swine, alpaca, bison,camel, cattle, chinchilla, deer, donkey, duck, fish, frog, goat, goose,fowl, horse, llama, mink, mule, ostrich, pigeon, reindeer, sheep,turkey, yak, water buffalo cat, chimpanzee, dog, ferret, gerbil,goldfish, guinea pig, hamster, monkey, parakeet, reptiles and rodents.and aquatic farm animals including fish and shellfish such as shrimp. Ascompared to the wild type phytase of SEQ. ID NO: 1, the phytase variantsof this disclosure can provide improved resistance to the proteasesfound in such animals or may otherwise provide prolonged activity in thedigestive tracts of such animals. The present disclosure contemplates amethod for the production of a food or animal feed, characterized inthat phytase according to this disclosure is mixed with said food oranimal feed for any such animal. The liquid compositions can be added toa food or feed after an optional pelleting thereof. In some embodiments,the animal feed will comprise one or more of the following components:a) cereals, such as small grains (e.g., wheat, barley, rye, oats andcombinations thereof) and/or large grains such as maize or sorghum; b)by products from cereals, such as corn gluten meal, Distillers DriedGrain Solubles (DDGS), wheat bran, wheat middlings, wheat shorts, ricebran, rice hulls, oat hulls, palm kernel, and citrus pulp; c) proteinobtained from sources such as soya, sunflower, peanut, lupin, peas, favabeans, cotton, canola, fish meal, dried plasma protein, meat and bonemeal, potato protein, whey, copra, sesame; d) oils and fats obtainedfrom vegetable and animal sources; e) minerals and vitamins; f)supplements, such as enzymes, betaine, flavors, essential oils,antibiotic growth promoters, coccidiostats, probiotics, and prebiotics.

Also provided is a method for the reduction of levels of phosphorus inanimal manure, characterized in that an animal is fed with an animalfeed comprising a phytase variant according to this disclosure in anamount effective in converting phytate contained in said animal feed.

Further the phytase compositions encompassed by this disclosure may beused in methods of starch hydrolysis. The phytase composition may beadded during a starch liquefaction step, a saccharification step and/orduring a fermentation step. Alpha-amylases are used to break down starch1-4 linkages during industrial starch hydrolysis processes using reducedplant material such as milled grains as a feedstock (e.g. infermentation processes, brewing, and baking). Amylases are required tobreak down starch and obtaining adequate activity of these enzymes issometimes problematic. It has been known for some time that phytate hasan inhibitory effect on amylases. Therefore enzyme compositionscomprising a phytase according to this disclosure may be used in starchhydrolysis process to reduce the inhibitory effect of phytate on alphaamylase (EP 0 813607B1).

Phytases, phytate and lower phosphate phytate derivatives find manyother uses in personal care products, medical products and food andnutritional products, as well as various industrial applications,particularly in the cleaning, textile, lithographic and chemical arts.Advantageously, for example, phytase variants according to embodimentsof the present disclosure can be used in alcohol fermentation, e.g. forthe production of biofuel.

Use of Phytases

As stated above, the present invention also relates to the production ofphytases as described herein.

In particular, the present invention also relates to the use of theamino acid sequences as disclosed herein in the production of organicand inorganic phosphate compounds.

Thus, the present invention further relates to the use of the nucleotidesequences encoding phytases in generating expression vectors or systemsfor the expression of the phytases.

In addition, the present invention relates to the use of such expressionvectors or systems in the generation of host cells which expressphytases.

The invention further relates to the use of modified host cells in thegeneration of precursors of organic and inorganic phosphate compounds orin the generation of specific organic phosphate compounds.

Suitable organic and inorganic phosphate compounds include myo-inositolpentakis-, tetrakis-, tris-, bis- and monophosphates.

Suitably, the invention therefore provides a method of producing anorganic phosphate compound comprising treating a phytate with a phytaseaccording to the present invention. Suitably, the organic phosphate isphytate or all possible stereoisomers of myo-inositol di-, tri-, tetra,and pentaphosphates. Other suitable organic phosphates includeinositol-tetraphosphates and inositol-oligophosphates. In a preferredembodiment, the method is an in vivo biotechnological process.

Such methods for producing an organic phosphate compound may suitablycomprise the steps of:

-   -   a) providing a host cell that comprises expressible transgenes        comprising the phytase of the invention;    -   b) culturing the transgenic organism under conditions suitable        for expression of the transgene; and    -   c) recovering the organic phosphate compound from the culture.

The compounds can be used for a number of applications including inassays for the characterisation of phytases. Some inositol phosphatesare involved as signal molecules in intracellular regulation and can beused research chemicals.

In another aspect there is provided a method for production of food oranimal feed. Animal feed is typically produced in feed mills in whichraw materials are first ground to a suitable particle size and thenmixed with appropriate additives. The feed may then be produced as amash or pellets; the later typically involves a method by which thetemperature is raised to a target level and then the feed is passedthrough a die to produce pellets of a particular size. Subsequentlyliquid additives such as fat and enzyme may be added. The pellets areallowed to cool prior to transportation. Production of animal feed mayalso involve an additional step that includes extrusion or expansionprior to pelleting—in particular by suitable techniques, that mayinclude at least the use of steam.

Accordingly, the invention further provides the use of an amino acidsequence encoding a phytase or a host cell expressing a phytase toproduce a phytase for use in the manufacture of a food or feed product.In one aspect, there is provided a use of an amino acid sequence asdescribed herein in the manufacture of a food or feed product. Inanother aspect, there is provided a use of a host cell in accordancewith the invention in the manufacture of a food or feed product. Inanother aspect, there is provided a use of an expression vector orsystem in accordance with the invention in the manufacture of a food orfeed product.

The present invention also covers using the enzymes as a component offeed combinations with other components to deliver to animals.

Combination with Other Components

The enzymes of the present invention may be used in combination withother components or carriers. Examples of other components have alreadybeen provided herein. These and other additional components are nowdiscussed.

Suitable carriers for feed enzymes include wheat (coarsely ground). Inaddition there are a number of encapsulation techniques including thosebased on fat/wax coverage, adding plant gums etc.

Examples of other components include one or more of: thickeners, gellingagents, emulsifiers, binders, crystal modifiers, sweetners (includingartificial sweeteners), rheology modifiers, stabilisers, anti-oxidants,dyes, enzymes, carriers, vehicles, excipients, diluents, lubricatingagents, flavouring agents, colouring matter, suspending agents,disintegrants, granulation binders etc. These other components may benatural. These other components may be prepared by use of chemicaland/or enzymatic techniques.

As used herein the term “thickener or gelling agent” as used hereinrefers to a product that prevents separation by slowing or preventingthe movement of particles, either droplets of immiscible liquids, air orinsoluble solids.

The term “stabiliser” as used here is defined as an ingredient orcombination of ingredients that keeps a product (e.g. a food product)from changing over time.

The term “emulsifier” as used herein refers to an ingredient (e.g. afood product ingredient) that prevents the separation of emulsions.

As used herein the term “binder” refers to an ingredient (e.g. a foodingredient) that binds the product together through a physical orchemical reaction.

The term “crystal modifier” as used herein refers to an ingredient (e.g.a food ingredient) that affects the crystallisation of either fat orwater.

“Carriers” or “vehicles” mean materials suitable for compoundadministration and include any such material known in the art such as,for example, any liquid, gel, solvent, liquid diluent, solubiliser, orthe like, which is non-toxic and which does not interact with anycomponents of the composition in a deleterious manner.

Examples of nutritionally acceptable carriers include, for example,grain, water, salt solutions, alcohol, silicone, waxes, petroleum jelly,vegetable oils, and the like.

Examples of excipients include one or more of: microcrystallinecellulose and other celluloses, lactose, sodium citrate, calciumcarbonate, dibasic calcium phosphate, glycine, starch, milk sugar andhigh molecular weight polyethylene glycols.

Examples of disintegrants include one or more of: starch (preferablycorn, potato or tapioca starch), sodium starch glycollate,croscarmellose sodium and certain complex silicates.

Examples of granulation binders include one or more of:polyvinylpyrrolidone, hydroxypropylmethylcellulose (HPMC),hydroxypropylcellulose (HPC), sucrose, maltose, gelatin and acacia.

Examples of lubricating agents include one or more of: magnesiumstearate, stearic acid, glyceryl behenate and talc.

Examples of diluents include one or more of: water, ethanol, propyleneglycol and glycerin, and combinations thereof.

The other components may be used simultaneously (e.g when they are inadmixture together or even when they are delivered by different routes)or sequentially (e.g they may be delivered by different routes).

As used herein the term “component suitable for animal or humanconsumption” means a compound which is or can be added to thecomposition of the present invention as a supplement which may be ofnutritional benefit, a fibre substitute or have a generally beneficialeffect to the consumer.

By way of example, the components may be prebiotics such as alginate,xanthan, pectin, locust bean gum (LBG), inulin, guar gum,galacto-oligosaccharide (GOS), fructo-oligosaccharide (FOS),lactosucrose, soybean oligosaccharides, palatinose,isomalto-oligosaccharides, gluco-oligosaccharides andxylo-oligosaccharides.

Food or Feed Substance

The compounds may be used as—or in the preparation of—a food or feedsubstance. Here, the term “food” is used in a broad sense—and coversfood and food products for humans as well as food for animals (i.e. afeed). The term “feed” is used with reference to products that are fedto animals in the rearing of livestock. In a preferred aspect, the foodor feed is for consumption by monogastric animals such as pig, poultryand fish.

The food or feed may be in the form of a solution or as asolid—depending on the use and/or the mode of application and/or themode of administration.

Food and Feed Ingredients and Supplements

The compounds may be used as a food or feed ingredient.

As used herein the term “food or feed ingredient” includes aformulation, which is or can be added to foods or foodstuffs andincludes formulations which can be used at low levels in a wide varietyof products.

The food ingredient may be in the form of a solution or as asolid—depending on the use and/or the mode of application and/or themode of administration.

The compounds may be—or may be added to—food supplements.

Foods and Feed Compositions

Feed compositions for monogastric animals typically include compositionscomprising plant products which contain phytate. Such compositionsinclude cornmeal, soybean meal, rapeseed meal, cottonseed meal, maize,wheat, barley and sorghum-based feeds.

The phytases described herein may be—or may be added to—foods or feedsubstances and compositions.

The present invention also provides a method of preparing a food or afeed ingredient or supplement, the method comprising admixing phytasesproduced by the process of the present invention or the compositionaccording to the present invention with another food ingredient. Themethod for preparing or a food ingredient is also another aspect of thepresent invention. Methods for preparing animal feed are set out above.The enzyme can be added also in the form of a solid formulation, or as afeed additive, such as a pre-mix. A solid form is typically added beforeor during the mixing step; and a liquid form is typically added afterthe pelleting step.

Forms

The product and/or the compounds of the present invention may be used inany suitable form—whether when alone or when present in a composition.Likewise, phytases produced in accordance with the present invention(i.e. ingredients—such as food ingredients, functional food ingredientsor pharmaceutical ingredients) may be used in any suitable form.

Suitable examples of forms include one or more of: tablets, pills,capsules, ovules, solutions or suspensions, which may contain flavouringor colouring agents, for immediate-, delayed-, modified-, sustained-,pulsed- or controlled-release applications.

By way of example, if the product and/or the composition are used in atablet form—such as for use as a functional ingredient—the tablets mayalso contain one or more of: excipients, disintegrants, granulationbinders, or lubricating agents.

Examples of nutritionally acceptable carriers for use in preparing theforms include, for example, water, salt solutions, alcohol, silicone,waxes, petroleum jelly and the like.

Preferred excipients for the forms include lactose, starch, a cellulose,milk sugar or high molecular weight polyethylene glycols.

For aqueous suspensions and/or elixirs, the phytase cleavage compoundsmay be combined with various sweetening or flavouring agents, colouringmatter or dyes, with emulsifying and/or suspending agents and withdiluents such as water, ethanol, propylene glycol and glycerin, andcombinations thereof.

The forms may also include gelatin capsules; fibre capsules, fibretablets etc.

The following examples are offered for illustrative purposes only, andare not intended to limit the scope of the present disclosure in anyway.

METHODS AND EXAMPLES Nomenclature for Enzymes Used in the Examples

Phytase BP-17 (sometimes referred to as BP 17)—which is the phytasedescribed in at least PCT application WO 2008/097619 and which may beobtained from Danisco A/S. The amino acid sequence is described hereinas SEQ ID NO:5.

BP-110 (sometimes referred to as BP 17 var. 110, or sometimes it isreferred to as BP17-110 or BP17 110)—which is the phytase according tothe present invention and which may be obtained from Danisco A/S. Theamino acid sequence is described herein as SEQ ID NO:6.

BP-111 (sometimes referred to as BP 17 var. 111, or sometimes it isreferred to as BP17-111 or BP17 111)—which is the phytase according tothe present invention and which may be obtained from Danisco A/S. Theamino acid sequence is described herein as SEQ ID NO:7.

BP-112 (sometimes referred to as BP 17 var. 112, or sometimes it isreferred to as BP17-112 or BP17 112)—which is the phytase according tothe present invention and which may be obtained from Danisco A/S. Theamino acid sequence is described herein as SEQ ID NO:2.

The amino acid sequences for BP-17 (SEQ ID NO: 5), BP-110 (SEQ ID NO:6),BP-111 (SEQ ID NO:7) and BP-112 (SEQ ID NO:2) are presented in FIG. 5.The amino acid sequence of BP-112 is also shown in FIG. 2. The nucleicacid sequence of BP-112 is shown in FIG. 4 as SEQ ID NO:4.

Phyzyme XP—which is a phytase from Danisco A/S

Natuphos—which is a phytase from BASF.

Ronozyme P—which is a phytase from Novozymes.

Part A Example 1 Purification of Phytase Enzymes

Purification of phytase enzymes was performed using a 6His-tagN-terminally fused to the phytase enzymes. B. subtilis, transformed witha plasmid coding for the 6His-tagged phytase enzyme, was cultivated inshake flasks at 37° C. and 160 rpm using standard LB medium withaddition of 20 mg/l Neomycin. At this stage, the culture mediumaccumulated significant amount of phytase activity. About 2 l of theculture broth were adjusted to pH 8.0, filtered and applied to a columnpacked with 10 ml of Ni-NTA sepharose resin (Qiagen). The column waswashed with 50 mM Tris-HCl buffer, 300 mM NaCl, pH 8.0 until OD280dropped below 0.05. Subsequently the bound phytase was eluted with thesame buffer containing 250 mM imidazole hydrochloride. The elutate wasdialysed against 50 mM sodium acetate buffer pH 5.0 and stored at 4° C.The enzyme solution was then applied to a Resource S column equilibratedwith 20 mM sodium acetate buffer pH 5.0 and the elution was performedusing a salt gradient from 0-1 M NaCl over 10 column volumes. Optionallythe eluate was dialysed against 20 mM sodium acetate buffer pH 5.0before storing at 4° C.

Example 2 Phytase Activity Assay

Phytase assays were carried out in microtiter plates. The reaction had atotal volume of 100 microliter containing buffer, as described below, 10mM phytate, 1 mM calcium chloride and 0.05% (w/v) Pluronic F68. Thereaction was allowed to proceed for 30 minutes at a given temperature,e.g. between 37° C. and 90° C.

Phosphate liberation from phytate as a measure of the phytase activitywas assayed by incubating aliquots of the samples (typically 5 μl) in atotal volume of 50 μl of phosphate detection assay for 1 h at 37° C. Theassay contained the following compounds at the given finalconcentrations: 1 M Tris/HCl, pH 7.0, 0.01% (v/v) Triton X-100, 0.025 mMADHP (MoBiTec, Gottingen, Germany), 0.2 U/ml maltosephosphorylase, 0.25mM maltose, 1.25 U/ml glucose oxidase, 0.25 U/ml horseradish peroxidase,1 mM EDTA, 0.35 mg/ml BSA. The reaction was stopped by the addition of30 μl of 2700 U/ml catalase in H2O. Subsequently the fluorescence at 595nm was measured, using 535 nm as excitation wavelength. The amount ofphosphate was determined using a calibration curve with phosphatesolutions of known concentrations. One enzymatic unit is defined as theliberation of one micromole phosphate per minute.

For assaying phytase activity at different pH values the followingbuffers were used: 200 mM glycine/HCl from pH 2.0 to pH 3.5 and 100 mMsodium acetate/acetic acid between pH 4.0 and pH 5.5.

Example 3 Specific Activity

The specific activity of BP-WT and variant phytase enzymes was estimatedusing the purified enzymes according to example 1.

Phytase activity was determined in microtiter plates using a coupledenzymatic assay: Enzyme preparations were diluted in dilution buffer (50mM sodium acetate, 0.05% Pluronic F-68, 1 mg/ml BSA). An aliquot of theenzyme solution, typically 5 μl to 10 μl was incubated in the phytateassay with a total volume of 80 μl. The assay contains the followingbuffers, substrates and salts at the given final concentrations: 200 mMsodium acetate, pH 5.5, 10 mM phytate, 1 mM CaCl₂, 0.05% (w/v) PluronicF-68). The assays were incubated for 30 min at 37° C. in the case of theBP-WT phytase and for 30 min at 67° C. or 80° C. in the case of thevariant phytase enzymes.

Phosphate liberation from phytate as a measure of the phytase activitywas assayed by incubating aliquots of the respective samples (typically5 μl) in a total volume of 50 μl of phosphate detection assay for 1 h at37° C. The assay contained the following compounds at the given finalconcentrations: 1 M Tris/HCl, pH 7.0, 0.01% (v/v) Triton X-100, 0.025 mMADHP (MoBiTec, Gottingen, Germany), 0.2 U/ml maltosephosphorylase, 0.25mM maltose, 1.25 U/ml glucose oxidase, 0.25 U/ml horseradish peroxidase,1 mM EDTA, 0.35 mg/ml BSA. The reaction was stopped by the addition of30 μl of 2700 U/ml catalase in H2O. Subsequently the fluorescence at 595nm was measured, using 535 nm as excitation wavelength. The amount ofphosphate was determined using a calibration curve with phosphatesolutions of known concentrations. One enzymatic unit is defined as theliberation of one micromole phosphate per minute.

Phytase concentration was calculated from the absorbance of thepreparations at 280 nm and the respective extinction coefficient foreach of each phytase variant. The extinction coefficients werecalculated on the basis of the amino acid composition of the proteinsaccording to a method provided by Gill and von Hippel, AnalyticalBiochemistry 182:319-326 (1989).

TABLE 1 Specific activity of phytase variants according to BP-WT, Seq IDNo. 1. The specific activity of the variant phytase enzymes wasdetermined at 67° C. and 80° C. as described above. The BP-WT enzyme hasa specific activity of 1021 U/mg at 37° C. under the conditionsdescribed above. Specific activity Specific activity Variant at 67°C./[U/mg] at 80° C./[U/mg] N37Y/S75P/A89T/D92A/T134I/H160R/F164E/T171V/2381 2592 T176K/A178P/S188P/G192A/K198R/K207E/A209S/S248L/Q256Y/A261E/N270K/A374P [BP-112]N37Y/G77S/A89T/D92A/T134I/H160R/F164E/T171V/ 2192 2315T176K/A178P/S188P/G192A/K198R/K207E/A209S/S 248L/Q256Y/A261E/N270K/A374P[BP-110] N37Y/S75P/Q76R/A89T/D92A/T134I/H160R/F164E/T 2065 2052171I/T176K/A178P/S188P/G192A/K207E/A209S/A235V/S248L/Q256Y/A261E/N270K/A374P [BP-111]N37Y/A89T/D92A/T134I/F164E/T171V/T176K/A178 1725 1652P/G192A/K207E/A209S/A235V/S248L/Q256P/A261E/ N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171I/T 1680 1481176K/A178P/S188P/G192A/K207E/A209S/S248L/Q25 6Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/H160R/F164E/T171I/ 2441 1948T176K/A178P/S188P/G192A/K207E/A209S/S248L/Q 256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164S/T171V/T176K/ 1613 1412A178P/S188P/G192A/K207E/A209S/A235V/S248L/Q 256A/A261E/N270K/A374PS75P/A89T/D92A/T134I/F164E/T171V/T176K/A178P/ 2171 1820S188P/G192A/K207E/A209S/A235V/S248L/Q256Y/ A261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171V/ 2421 2038T176K/A178P/S188P/G192A/K207E/A209S/A235V/S248L/Q256Y/A261E/N270K/P367L/A374PN37Y/A89T/D92A/T134I/F164E/T171I/T176K/A178P/ 2314 1752G192A/K207E/A209S/A235V/S248L/Q256Y/A261E/ N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164E/T171V/T176K/ 2251 1783A178P/G192A/K207E/A209S/S248L/Q256Y/A261E/ N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164E/T171V/T176K/ 1597 1289A178P/G192A/K207E/A209S/S248L/Q256A/A261E/ N270K/A374PN37Y/S75P/Q76R/A89T/D92A/T134I/F164E/T171V/T 1651 1104176K/A178P/K207E/A209S/A235V/S248L/Q256A/A2 61E/N270K/A374PN37Y/S75P/A89T/D92A/T134I/H160R/F164E/T171V/ 2378 1750T176K/A178P/K207E/A209S/A235V/S248L/Q256Y/A 261E/N270K/A374PN37Y/A89T/D92A/T134I/H160R/F164S/T171I/T176K/ 2010 1392A178P/S188P/G192A/K207E/A209S/A235V/S248L/Q 256E/A261E/N270K/A374PA89T/D92A/T134I/H160R/F164E/T171V/T176K/A17 2161 14688P/G192A/K207E/A209S/A235V/S248L/Q256Y/A261 E/N270K/A374PN37Y/S75P/A89T/D92A/T134I/H160R/F164S/T171V/ 2421  962T176K/A178P/S188P/K207E/A209S/S248L/Q256H/A 261E/N270K/A374PN37Y/S75P/A89T/D92A/T134I/F164S/T171V/T176K/ 1866 998A178P/S188P/G192A/K207E/A209S/S248L/Q256A/A 261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171V/ 1755  843T176K/A178P/G192A/K207E/A209S/S248L/Q256A/A 261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/H160R/F164S/T171V/ 2476 1654T176K/A178P/G192A/K207E/A209S/A235V/S248L/ Q256Y/A261E/N270K/A374P

Example 4 Generation and Characterization of Phytase Variants

Phytase variants were generated using different methods for themutagenesis of the DNA encoding the phytase proteins like cassette orPCR mutagenesis or other mutagenesis methods well known in the art.Those methods comprise the ones listed above such as the methodsdisclosed in Morinaga et al., Biotechnology 2:646-649 (1984); in Nelsonand Long, Analytical Biochemistry 180:147-151 (1989); or the ErrorThreshold Mutagenesis protocol described in WO 92/18645. For mutagenicPCR another suitable method is disclosed by Cadwell and Joyce, PCRMethods Appl. 3:136-140 (1994).

Phytase variants were heterologously expressed in one or more of thefollowing expression hosts: Saccharomyces cerevisiae, Bacillus subtilis,Escherichia coli.

Example 5 Thermal Stability

The thermal stability of phytase variants was characterized by theirinactivation temperature. The inactivation temperature was determined bythe residual activity of the phytase enzymes after incubation for 10 minat different temperatures, pH 5.5 and subsequent incubation at 37° C.for 60 min. Residual activities were determined measuring phytaseactivities for 60 min at pH 3.5 and 37° C. The inactivation temperatureis defined as the temperature at which the residual activity is 50%compared to the residual activity after incubation for the same durationunder the same conditions at room temperature. Where appropriateextrapolations and interpolations from the activity data were made inorder to determine the temperature corresponding to 50% residualactivity. Thermal stability differences (TD) in [° C.] were calculatedby subtracting the inactivation temperatures of two enzymes from eachother.

TABLE 2 Thermal stability of phytase variants according to BT-WT, Seq IDNo. 1. Improvements in thermal stability are presented as thermalstability differences TD between variant and wild-type (BP-WT) phytaseenzyme, i.e. TD = (inactivation temperature of the variant phytase) −(inactivation temperature of BP-WT). Variant TD/[° C.]N37Y/S75P/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/S188P/G19 26.52A/K198R/K207E/A209S/S248L/Q256Y/A261E/N270K/A374P [BP-112]N37Y/G77S/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/S188P/G1 25.992A/K198R/K207E/A209S/S248L/Q256Y/A261E/N270K/A374P [BP-110]N37Y/S75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171I/T176K/A178P/S188 26.8P/G192A/K207E/A209S/A235V/S248L/Q256Y/A261E/N270K/A374P [BP-111]N37Y/A89T/D92A/T134I/F164E/T171V/T176K/A178P/G192A/K207E/A209S/A 23.7235V/S248L/Q256P/A261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171I/T176K/A178P/S188P/G19 24.22A/K207E/A209S/S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/H160R/F164E/T171I/T176K/A178P/S188P/G19 25.02A/K207E/A209S/S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164S/T171V/T176K/A178P/S188P/G192A/K2 22.607E/A209S/A235V/S248L/Q256A/A261E/N270K/A374PS75P/A89T/D92A/T134I/F164E/T171V/T176K/A178P/S188P/G192A/K207E/A2 24.909S/A235V/S248L/Q256Y/A261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/S188P/G19 24.12A/K207E/A209S/A235V/S248L/Q256Y/A261E/N270K/P367L/A374PN37Y/A89T/D92A/T134I/F164E/T171I/T176K/A178P/G192A/K207E/A209S/A 23.4235V/S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164E/T171V/T176K/A178P/G192A/K207E/A 23.5209S/S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164E/T171V/T176K/A178P/G192A/K207E/A 24.4209S/S248L/Q256A/A261E/N270K/A374PN37Y/S75P/Q76R/A89T/D92A/T134I/F164E/T171V/T176K/A178P/K207E/A20 22.49S/A235V/S248L/Q256A/A261E/N270K/A374PA89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/G192A/K207E/A209S/ 23.5A235V/S248L/Q256Y/A261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/G192A/K2 22.907E/A209S/S248L/Q256A/A261E/N270K/A374P

Example 6 Thermal Activity

The thermal activity of phytase variants was characterized by theirtemperature-activity profile. As a measure of the temperature-activityprofile the value T50 was defined, at which the total enzymatic turnoverof the substrate is 50% compared to the total enzymatic turnover of thesubstrate in a reaction running essentially under the same conditionsbut at the temperature optimum of the phytase variant. Thetemperature-activity profiles were determined by incubation of thephytase enzymes at pH 5.5 and various temperatures under conditionsfurther described in Example 2. T50 values were determined byappropriate interpolations and extrapolations from the experimentaldata. Thermal activity differences (TAD) in [° C.] were calculated bysubtracting the T50 values of two enzymes from each other.

TABLE 3 Thermal activity differences (TAD) of phytase variants accordingto BT-WT, Seq ID No: 1. Improvements in thermal activity are given asT50 differences between variant and wild-type (BP-WT) phytase enzyme,i.e. TAD = T50(variant phytase) − T50(BP-WT). TAD/ Variant [° C.]N37Y/S75P/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/S188P/G 20.2192A/K198R/K207E/A209S/S248L/Q256Y/A261E/N270K/A374P [BP-112]N37Y/G77S/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/S188P/G 20.0192A/K198R/K207E/A209S/S248L/Q256Y/A261E/N270K/A374P [BP-110]N37Y/S75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171I/T176K/A178P/S18 20.18P/G192A/K207E/A209S/A235V/S248L/Q256Y/A261E/N270K/A374P [BP-111]N37Y/A89T/D92A/T134I/F164E/T171V/T176K/A178P/G192A/K207E/A209S/ 19.5A235V/S248L/Q256P/A261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171I/T176K/A178P/S188P/G1 19.392A/K207E/A209S/S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/H160R/F164E/T171I1/T176K/A178P/S188P/G1 19.392A/K207E/A209S/S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164S/T171V/T176K/A178P/S188P/G192A/K 18.9207E/A209S/A235V/S248L/Q256A/A261E/N270K/A374PS75P/A89T/D92A/T134I/F164E/T171V/T176K/A178P/S188P/G192A/K207E/A 19.02095/A235V/S248L/Q256Y/A261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/S188P/G1 18.992A/K207E/A209S/A235V/S248L/Q256Y/A261E/N270K/P367L/A374PN37Y/A89T/D92A/T134I/F164E/T171I/T176K/A178P/G192A/K207E/A209S/ 18.8A235V/S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164E/T171V/T176K/A178P/G192A/K207E/ 18.7A209S/S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164E/T171V/T176K/A178P/G192A/K207E/ 18.9A209S/S248L/Q256A/A261E/N270K/A374PN37Y/S75P/Q76R/A89T/D92A/T134I/F164E/T171V/T176K/A178P/K207E/A2 18.409S/A235V/S248L/Q256A/A261E/N270K/A374PN37Y/S75P/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/K207E/A 17.9209S/A235V/S248L/Q256Y/A261E/N270K/A374PN37Y/A89T/D92A/T134I/H160R/F164S/T171I/T176K/A178P/S188P/G192A/K 17.9207E/A209S/A235V/S248L/Q256E/A261E/N270K/A374PA89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/G192A/K207E/A209S/ 17.8A235V/S248L/Q256Y/A261E/N270K/A374PN37Y/S75P/A89T/D92A/T134I/H160R/F164S/T171V/T176K/A178P/S188P/K2 17.807E/A209S/S248L/Q256H/A261E/N270K/A374PN37Y/S75P/A89T/D92A/T134I/F164S/T171V/T176K/A178P/S188P/G192A/K 17.4207E/A209S/S248L/Q256A/A261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F164E/T171V/T176K/A178P/G192A/K 17.5207E/A209S/S248L/Q256A/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/H160R/F164S/T171V/T176K/A178P/G192A/ 17.6K207E/A209S/A235V/S248L/Q256Y/A261E/N270K/A374P

Example 7 Properties Overview of Phytase Variants

i) Table 4 summarizes the properties specific activity, thermalstability and thermal activity of phytase variants that were beforepresented in examples 3, 5 and 6.

TABLE 4 Specific activity, thermal stability and thermal activity ofdifferent phytase variants according to BT-WT, Seq ID No: 1. Values forspecific activities, thermal stability (TD), and thermal activity (TAD)were derived as described in example 3, example 5 and example 6,respectively. Specific Specific TD/ TAD/ activity at activity at Variant[° C.] [° C.] 67° C./[U/mg] 80° C./[U/mg]N37Y/S75P/A89T/D92A/T134I/H160R/F1 26.5 20.2 2381 259264E/T171V/T176K/A178P/S188P/G192A/ K198R/K207E/A209S/S248L/Q256Y/A261E/N270K/A374P [BP-112] N37Y/G77S/A89T/D92A/T134I/H160R/F1 25.9 20.0 21922315 64E/T171V/T176K/A178P/S188P/G192A/K198R/K207E/A209S/S248L/Q256Y/A261 E/N270K/A374P [BP-110]N37Y/S75P/Q76R/A89T/D92A/T134I/H16 26.8 20.1 2065 20520R/F164E/T171I/T176K/A178P/S188P/G1 92A/K207E/A209S/A235V/S248L/Q256Y/A261E/N270K/A374P [BP-110] N37Y/A89T/D92A/T134I/F164E/T171V/T 23.7 19.51725 1652 176K/A178P/G192A/K207E/A209S/A235V/S248L/Q256P/A261E/N270K/A374P S75P/Q76R/A89T/D92A/T134I/H160R/F16 24.219.3 1680 1481 4E/T171I/T176K/A178P/S188P/G192A/K207E/A209S/S248L/Q256Y/A261E/N270K/ A374PN37Y/Q76R/A89T/D92A/T134I/H160R/F1 25.0 19.3 2441 194864E/T171I/T176K/A178P/S188P/G192A/K 207E/A209S/S248L/Q256Y/A261E/N270K/A374P N37Y/Q76R/A89T/D92A/T134I/F164S/T1 22.6 18.9 1613 141271V/T176K/A178P/S188P/G192A/K207E/ A209S/A235V/S248L/Q256A/A261E/N270K/A374P S75P/A89T/D92A/T134I/F164E/T171V/T1 24.9 19.0 2171 182076K/A178P/S188P/G192A/K207E/A209S/ A235V/S248L/Q256Y/A261E/N270K/A37 4PS75P/Q76R/A89T/D92A/T134I/H160R/F16 24.1 18.9 2421 20384E/T171V/T176K/A178P/S188P/G192A/K 207E/A209S/A235V/S248L/Q256Y/A261E/N270K/P367L/A374P N37Y/A89T/D92A/T134I/F164E/T171I/T1 23.4 18.8 23141752 76K/A178P/G192A/K207E/A209S/A235V/ S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164E/T1 23.5 18.7 2251 178371V/T176K/A178P/G192A/K207E/A209S/ S248L/Q256Y/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I/F164E/T1 24.4 18.9 1597 128971V/T176K/A178P/G192A/K207E/A209S/ S248L/Q256A/A261E/N270K/A374PN37Y/S75P/Q76R/A89T/D92A/T134I/F16 22.4 18.4 1651 11044E/T171V/T176K/A178P/K207E/A209S/A 235V/S248L/Q256A/A261E/N270K/A374PN37Y/S75P/A89T/D92A/T134I1H160R/F1 n.d. 17.9 2378 175064E/T171V/T176K/A178P/K207E/A209S/ A235V/S248L/Q256Y/A261E/N270K/A37 4PN37Y/A89T/D92A/T134I/H160R/F164S/T n.d. 17.9 2010 13921711/T176K/A178P/S188P/G192A/K207E/ A209S/A235V/S248L/Q256E/A261E/N270K/A374P A89T/D92A/T134I/H160R/F164E/T171V/ 23.5 17.8 2161 1468T176K/A178P/G192A/K207E/A209S/A235 V/S248L/Q256Y/A261E/N270K/A374PN37Y/S75P/A89T/D92A/T134I/H160R/F1 n.d. 17.8 2421  96264S/T171V/T176K/A178P/S188P/K207E/A 209S/S248L/Q256H/A261E/N270K/A374PN37Y/S75P/A89T/D92A/T134I1F164S/T17 n.d. 17.4 1866  9981V/T176K/A178P/S188P/G192A/K207E/A 209S/S248L/Q256A/A261E/N270K/A374PS75P/Q76R/A89T/D92A/T134I/H160R/F16 22.9 17.5 1755  8434E/T171V/T176K/A178P/G192A/K207E/A 209S/S248L/Q256A/A261E/N270K/A374PN37Y/Q76R/A89T/D92A/T134I1H160R/F1 n.d. 17.6 2476 165464S/T171V/T176K/A178P/G192A/K207E/ A209S/A235V/S248L/Q256Y/A261E/N270K/A374P

Part B Example 8 Introduction

The present invention is advantageous as it provides for novel phytasesthat have properties making them particularly useful and efficient asfeed enzymes. In particular the invention relates to isolated and/orpurified novel phytase polypeptides as described herein, or a functionalfragment, or variants or modified forms thereof, or modified formthereof. The invention also provides the nucleic acid sequence encodingsaid phytase.

To be efficient as an enzyme additive to food or animal feed, thephytase has to combine a number of different properties. In order to beable to degrade phytic acid in the acidic environment of an animal'sstomach it has to be active at low pH, preferably over a broad range ofpH values. In addition, it has to have high specific activity andpreferably high thermostability to enable the protein to withstand hightemperatures commonly used in preparation of feedstuffs such as feedpellets.

It is also important that the enzyme has broad substrate specificityallowing it to hydrolyse not only phytate but also intermediate productsof phytate degradation such as inositol pentaphosphates, tetraphosphatesand triphosphates. Studies on phytate degradation in pigs show thatthese inositol oligophosphates otherwise remain largely insoluble in thesmall and large intestine and thus inaccessible to alkaline phosphatasesproduced by the animal and gut microflora. Variations in substratespecificity profiles of different enzymes have been identified. Forexample, inositol-triphosphates generated by the phytase from B.subtilis are essentially resistant to further hydrolysis by this enzyme.

Suitably these variants show improved characteristics with respect toany one of the following: temperature stability, pH range, pepsinstability, specific activity, substrate specificity, and broadersubstrate specificity. Suitable methods for determining thesecharacteristics are disclosed herein.

In particular, the improvements in phytase characteristics are directedto the enzyme stability under food and feed processing conditions, tothe enzyme stability during stomach transit, and to the enzyme activityand stability in human or animal stomach and/or intestinal tract makingthe improved variants particularly suitable for use as feed supplements.Thus, such improvements comprise among other parameters the increase instability at elevated temperatures, preferably at temperatures above 65°C., the increase in stability against proteolytic digestion, preferablyprotease of the digestive tract such as pepsin, the increase incatalytic activity at low pH, preferably catalytic activity below pH5.5, and the general efficiency of releasing phosphate groups fromphytate, and preferably in addition inositol phosphates.

Improvements in phytase characteristics according to the presentinvention are directed to the use in food and feed processing as well asfor the use as an additive to food and feed products. In particular,improvements are directed to the stability under food and feedprocessing conditions, to the stability during stomach transit, and tothe activity and stability in human or animal stomach and/or intestinaltract. Such improvements comprise among other parameters the increase instability at elevated temperatures, preferably at temperatures above 65°C., the increase in stability against proteolytic digestion, preferablyprotease of the digestive tract, the increase in catalytic activity atlow pH, preferably catalytic activity below pH 5.5, and the generalefficiency of releasing phosphate groups from phytate.

The increase in stability at elevated temperatures is quantified by theinactivation temperature of the enzyme. The inactivation temperature isdefined as the temperature at which the residual activity of a phytaseenzyme after incubation for a certain duration and subsequent cooling toroom temperature is 50% of the residual activity of the same phytaseenzyme incubated for the same duration under the same conditions at roomtemperature. Thermostability differences are the differences in ° C.between the inactivation temperatures of two enzymes.

Example 9 Pepsin Stability

Pepsin resistance at pH 2 of phytases from Buttiauxella, variants BP-17,BP-110, BP-111, and BP-112, compared to Phyzyme XP, Natuphos, andRonozyme P

Materials and Methods Buffers:

Pepsin incubation buffer: 0.1 M Glycine-HCl, pH 2.0, 3 mg/ml BSA, 2.9 mgSodium chloride anhydrous/mL, 0.73 mg calcium chloride/mL. For solutionswith pepsin, the incubation buffer is prepared to contain 500, 1000,3000, 6000, or 10000 U/ml of pepsin (Sigma P-7000, 10000 U/mgcorresponds to 27 mg/ml), respectively. One pepsin unit is defined asthe amount of enzyme that will produce a ΔOD₂₈₀ of 0.001 per min at pH2.0 at 37° C., measured as TCA-soluble products using hemoglobin assubstrate (Food Chemical Codex).

Phytase assay buffer: Acetate buffer 250 mM, pH 5.5

Phytase assay buffer with BSA: Acetate buffer 250 mM, pH 5.5, with 3mg/ml BSA

Resistance Against Increasing Pepsin Concentration:

The set-ups for all enzymes were the same: Six samples with enzyme wereprepared (in duplicate): Four samples with increasing amount of pepsinin buffer (pH 2), one sample without pepsin but in incubation buffer (pH2), and one positive control sample with enzyme in assay buffer with BSA(pH 5.5).

For each sample, 900 μl incubation buffer without or with increasingamounts of pepsin or 900 μl assay buffer were mixed with 100 μl enzymesolution followed by incubation at 40° C. After 120 min incubation, 100μl was withdrawn and mixed with 900 μl assay buffer. Samples wereimmediately analysed for phytase at pH 5.5 against phosphate standardcurve as described by ISO draft international standard ISO/DIS 30024.

Results Pepsin Resistance

The Buttiauxella variants all showed excellent stability towards pepsinat pH 2. In contrast, the activity of Natuphos was reduced dramaticallyalready at a pepsin concentration of 500 U/ml, with further reducedactivity finding a plateau of about 45% recovery at a pepsinconcentration 3000 U/ml. The recovery of Ronozyme P was even worse witha reduction in recovery of less than 20% at a pepsin concentration ofonly 500 U/mg (FIG. 6A & Table 4).

FIG. 6 shows the resistance of the phytases originating fromButtiauxella, variants BP-17, BP-110, BP-111, and BP-112, and of PhyzymeXP, Natuphos, and Ronozyme P against increasing concentrations ofpepsin. Data are relative to incubation at pH 2 without pepsin. A: alldata points, B: same data but showing only more than 70% recovery.

TABLE 5 Same data as presented in Fig. 6 Pepsin level BP-17 BP-17 v. 110BP-17 v. 111 BP-17 v. 112 Phyzyme XP Natuphos Ronozyme P, new 0 100%100% 100% 100% 100% 100% 100% 500  87%  96%  98%  85%  61%  19% 1000 81%  98%  96%  85%  51%  16% 3000  82%  96%  94%  84%  93%  44%  17%6000  82%  92%  89%  80%  89%  45%  18% 10000  86%  95%  94%  79%  98% 46%  21%

There are slight differences between the Buttiauxella variants, wherevariant BP-17 var. 110 shows best stability having 95% activity leftafter two hours of incubation at the highest pepsin concentration, 10000U/mL (FIG. 6B). In comparison, BP-17 showed a recovery of around 85%after two hours of incubation.

The Buttiauxella phytases also showed excellent acid stability.Comparing the activity measured at pH 5.5 after two hours of incubationat either pH 2 or pH 5.5 showed that all four Buttiauxella phytases didnot lose activity during the 2 hours incubation at pH 2 whereas PhyzymeXP, Natuphos, and the new Ronozyme P showed slight to significantreduction in activity (Table 6).

TABLE 6 The activity measured at pH 5.5 after incubation in a buffer atpH 2 or pH 5.5 for two hours. The numbers are relative to the activityfrom the samples incubated at pH 5.5. BP-17 BP-17 v. 110 BP-17 v. 111BP-17 v. 112 Phyzyme XP Natuphos Ronozyme P, new Assay buffer 100% 100%100% 100% 100% 100% 100% pH 2, no pepsin 101% 102% 106% 120%  83%  90% 67%

Data Summary

The Buttiauxella phytase variants according to the present inventionshow more than 75% recovery after 2 hours of incubation at pH 2, 37° C.,10000 U/ml of pepsin compared to activity of the sample incubated underthe same condition but without pepsin present.

Example 10 Recovery of Enzyme Activity Evaluation of Recovery of EnzymeActivity Materials and Methods

Here, we evaluate the recovery of enzyme activity after pelleting of thewheat formulated enzyme. The enzyme is sprayed on granulated wheat anddried prior to mixing with feed followed by the pelleting process.

Liquid enzymes where formulated on whole grounded wheat and dried to adry matter content on approximately 90%. The inactivation of enzymesduring thermal stress in the pelleting process was tested using apelleting unit at the Technological Institute in Kolding (schematicallypresented in FIG. 7). Test sample is added to 10 kg premix and mixed for10 min. Then 10 kg premix was added to 150 kg feed (large horizontalmixer) and mixed for 15 min. before conditioning/steaming. Feed istreated 30 sec. at 90° C./95° C. before pelleting. The temperature ismeasured in the outlet of the cascade mixer. Immediately after leavingthe pelleting press the pellets are cooled to room temperature.

Phytase activity was measured according to the methodology recited inExample 10.

Phytase activity is 5 units per gm in the mash feed prior topelletising.

Results

The results are presented in FIGS. 8 to 10.

In FIG. 8, the results from the pelleting trials of three Phytase Bvariants according to the present invention is disclosed. The enzymeswere formulated on whole grounded wheat and dried to app 10% watercontent. Here, the recovery of phytase activity after pelleting for BP17 var 111 is 90% at 90° C. compared to a recovery of 19% at 90° C. forthe BP 17.

As reference is the Phyzyme XP, an E coli phytase was formulated onwhole grounded wheat. The results are shown in FIG. 9. Here, therecovery of phytase activity after being pelletised at 90° C. from thethree batches of Phyzyme XP formulated on whole grounded wheat is 47%.

Ronozyme was also tested. The product is sold in a coated version, toprotect the enzyme from the heat in the pelleting process. In this trialthe phytase was extracted from the coated product and formulated onwhole grounded wheat to study the themostability of the phytase moleculewithout protection. The results are shown in FIG. 10.

Data Summary

The Buttiauxella phytase variants of the present invention formulated onwheat show more than 70% recovery after being pelleted at 90° C.

Example 11 Phytic Acid Degradation

Results from a Study of Phytic Acid Degradation by Phytase

Solutions

Three different buffers were used in the incubations. They were asfollows:

250 mM acetate pH 5.5;

250 mM Acetate M pH 3.5; and

250 mM HCl glycine pH 2.5.

All phytases used on the incubations were diluted in assay buffer toenzyme level at 1 U/ml.

The phytate substrate solution used in the incubation is a Phytate 1% (1g/100 ml buffer).

The substrate is prepared in same buffer as used for the dilution ofphytases to keep the pH level constant in the reaction.

The reaction is terminated by 1M HCl.

Incubation

The incubation volumes are: 1.5 or 3.0 ml Phytate+0.25 ml enzyme+3.25 or1.75 ml buffer at 37° C., a total volume of 5.0 ml.

Sub-samples of 0.5 ml are taken at different time points (0, 30, 60 and90 min).

An eppendorf tube is prepared with a 0.2 ml 1M HCl for each sub-sampleprior to the sub-sampling. By blending the sub-sample from theincubation with HCl the enzyme reaction is terminated. Each sub-sampleof 0.7 ml is stored at 4° C. until HPLC analysis.

HPLC Method

Analysis of phytate and inositol isomers by high performance ionchromatography (HPIC). This method has been described by Skoglund andCarlsson et al. (J. Agric. Food Chem., 45 (1997), 451-436 5. J. Agric.Food Chem., 46 (1998), 1877-1882; and J. Agric. Food Chem., 49 (2001),11695-1701. The column used was a strong anion exchanger (4×250 mm) fromDionex with a pre-column of 4×50 mm. Solvent A, MilliQ water, Solvent B,1N HCl prepared in water. The gradient is from 2.5% to 49% B in 30 minfollowed by 3 min of isocratic at 50% and 2 min isocratic at 2.5% at aflow of 0.8 ml/min. Each run is 35 min. It is possible to reduce the runto totally 25 min as phytase does not produce so many theoreticallypossible IP isomers. The eluent was in-line derivatized with a watersolution containing 0.1% Fe(NO₃)₃.9HO₂ and 2% perchloric acid (HClO₄) ata flow of 0.4 ml/min. Phytate and IP isomers were detected at 290 nm asa positive peak. This is due to the formation of phytate-Fe³⁺—ClO₄ ⁻complex. A perchloric acid solution of 60% was bought from Sigma.

Results

The results are presented in FIGS. 11-14.

Data Summary

All of the enzymes of the present invention display favourablecharacteristics.

The phytases of the present invention break down phytate at all of thetested pH levels.The enzymes of the present invention are very active at pH 5.5.BP 110 and BP 111 display similar activity at pH 2.5 and 3.5.BP 110 and BP 111 break down all the phytate added to the incubationsafter 90 min at both pH 2.5 and pH 3.5BP112 breaks down 75% of the phytate added to the incubations after 90min at both pH 2.5 and pH 3.5

The enzymes of the present invention display better characteristics thanRonozyme and Natuphos at pH 2.5 (see at least FIG. 14) (Enzymeconcentration is higher than seen in FIGS. 11-13, so Buttiauxella BP17is there as reference.)

Example 12 Phytic Acid Hydrolysis in a Liquefact Phytic AcidDetermination:

Phytic acid content: Phytic acid was extracted from a sample byadjusting the pH of the 5% slurry (if it is dry sample) to pH 10 andthen determined by an HPLC method using an ion exchange column. Phyticacid was eluted from the column using a NaOH gradient system. Phyticacid content in the liquid was then calculated by comparing to a phyticacid standard.

Results

The effect of temperature on the hydrolysis of phytic acid of the wholeground corn liquefact from a conventional dry grind liquefaction process(source: Illinois River Energy, Monroe, Ill.) by different thermostableBP variant phytase, i.e., BP110, BP111 and BP112 was studied. The pH ofa 32% ds (“dry solid”) whole ground corn ds corn liquefact was adjustedto pH 5.0. and placed in a water bath maintained at 85° C. and 89° C.After temperature equilibration, BP-phytase was added at 4.0 FTU/gds.corn. Samples were then taken at 20 minutes and the enzyme reaction wasterminated by the addition of 10 mM sodium hydroxide (diluted 1 to 10fold). The diluted samples were then filtered and analyzed by HPLC fortheir phytate derivatives profile (IP1 to IP6). The HPLC chromatogramsin FIGS. 15 and 16 clearly showed that phytase from all three variantscatalyzed the hydrolysis of phytic acid at temperature greater than 85°C. The phytic acid content (phytic acid (IP6) and intermediates IP1 toIP5) in whole ground corn liquefact is around 1.7% ds.corn and data inFIG. 15 showed that more than 95% of the phytic acid was hydrolyzed bythermostable phytase under the current liquefaction conditions.Significantly, the HPLC profile from the samples incubated at 89° C.showed that the BP-111 phytase variant exhibited higher thermostabilitycompared to phytase from two other variants (see FIG. 16; BP-110 andBP-112).

Summary Aspects

Summary aspects of the present invention will now described by way ofnumbered paragraphs.

-   1. A phytase variant having phytase activity and an amino acid    sequence that varies from the amino acid sequence of the wild type    Buttiauxella sp. phytase (SEQ ID NO: 1), wherein the amino acid    sequence of the phytase variant comprises at least one variation as    compared with SEQ ID NO: 1, and wherein the at least one variation    occurs at a position selected from the group consisting of positions    75, 76 and 374 of SEQ ID NO: 1, and wherein each of said at least    one variations can be the same or different and can comprise a    substitution, deletion or insertion.-   2. A phytase of paragraph 1, wherein the at least one variation    comprises a variation of one, two or all three of the positions    selected from the group consisting of: S75, Q76 and A374.-   3. A phytase of paragraph 2, wherein the at least one variation    comprises a variation selected from the group consisting of: S75P,    Q76R and A374P.-   4. A phytase of paragraphs 1 to 3, wherein the at least one    variation also comprises a variation at one or more positions    selected from the group consisting of: N37, G77, H160, F164, T17I,    S188, G192, K198, A235, Q256 and/or P367.-   5. A phytase of paragraph 4, wherein the at least one variation    comprises a variation selected from the group consisting of: N37Y,    G77S, H160R, F164E, F164S, T171V, T171I, S188P, G192A, K198R, A235V,    Q256P, Q256A, Q256E and/or P367L.-   6. A phytase of paragraphs 1 to 5, wherein the at least one    variation also comprises a variation at one or more positions    selected from the group consisting of: A89, D92, T134, F164, T176,    A178, K207, A209, S248, Q256, A261 and/or N270.-   7. A phytase of paragraph 6, wherein the at least one variation    comprises a variation at one or more positions selected from the    group consisting of: A89T, D92A, T134I, F164S, T176K, A178P, K207E,    A209S, S248L, Q256Y, A261E and/or N270K.-   8. A phytase of paragraph 7, wherein said phytase comprises a    sequence of SEQ ID NO: 2.-   9. A phytase of any of paragraphs 1-8, wherein said phytase    comprises a sequence comprising variations selected from the group    consisting of:    -   a) N37Y, S75P, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, S188P, G192A, K198R, K207E, A209S, S248L, Q256Y, A261E,        N270K, A374P    -   b) N37Y, G77S, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, S188P, G192A, K198R, K207E, A209S, S248L, Q256Y, A261E,        N270K, A374P    -   c) N37Y, S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171I,        T176K, A178P, S188P, G192A, K207E, A209S, A235V, S248L, Q256Y,        A261E, N270K, A374P    -   d) N37Y, A89T, D92A, T134I, F164E, T171V, T176K, A178P, G192A,        K207E, A209S, A235V, S248L, Q256P, A261E, N270K, A374P    -   e) S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171I, T176K,        A178P, S188P, G192A, K207E, A209S, S248L, Q256Y, A261E, N270K,        A374P    -   f) N37Y, Q76R, A89T, D92A, T134I, H160R, F164E, T171I, T176K,        A178P, S188P, G192A, K207E, A209S, S248L, Q256Y, A261E, N270K,        A374P    -   g) N37Y, Q76R, A89T, D92A, T134I, F164S, T171V, T176K, A178P,        S188P, G192A, K207E, A209S, A235V, S248L, Q256A, A261E, N270K,        A374P    -   h) S75P, A89T, D92A, T134I, F164E, T171V, T176K, A178P, S188P,        G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P    -   i) S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, S188P, G192A, K207E, A209S, A235V, S248L, Q256Y, A261E,        N270K, P367L, A374P    -   j) N37Y, A89T, D92A, T134I, F164E, T171I, T176K, A178P, G192A,        K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P    -   k) N37Y, Q76R, A89T, D92A, T134I, F164E, T171V, T176K, A178P,        G192A, K207E, A209S, S248L, Q256Y, A261E, N270K, A374P    -   l) N37Y, Q76R, A89T, D92A, T134I, F164E, T171V, T176K, A178P,        G192A, K207E, A209S, S248L, Q256A, A261E, N270K, A374P    -   m) N37Y, S75P, Q76R, A89T, D92A, T134I, F164E, T171V, T176K,        A178P, K207E, A209S, A235V, S248L, Q256A, A261E, N270K, A374P    -   n) N37Y, S75P, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P    -   o) N37Y, A89T, D92A, T134I, H160R, F164S, T171I, T176K, A178P,        S188P, G192A, K207E, A209S, A235V, S248L, Q256E, A261E, N270K,        A374P    -   p) A89T, D92A, T134I, H160R, F164E, T171V, T176K, A178P, G192A,        K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P    -   q) N37Y, S75P, A89T, D92A, T134I, H160R, F164S, T171V, T176K,        A178P, S188P, K207E, A209S, S248L, Q256H, A261E, N270K, A374P    -   r) N37Y, S75P, A89T, D92A, T134I, F164S, T171V, T176K, A178P,        S188P, G192A, K207E, A209S, S248L, Q256A, A261E, N270K, A374P    -   s) S75P, Q76R, A89T, D92A, T134I, H160R, F164E, T171V, T176K,        A178P, G192A, K207E, A209S, S248L, Q256A, A261E, N270K, A374P;        and    -   t) N37Y, Q76R, A89T, D92A, T134I, H160R, F164S, T171V, T176K,        A178P, G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K,        A374P.-   10. A phytase which has at least a minimum percent sequence identity    and/or percent homology to the phytase of any of paragraphs 1-9,    wherein the minimum percent identity and/or homology is selected    from the group consisting of at least 50%, at least 60%, at least    75%, at least 80%, at least 85%, at least 90%, at least 93%, at    least 95%, at least 96%, at least 97%, at least 98%, and at least    99%.-   11. A phytase of any of paragraphs 1 to 10 having at least one    improved property as compared to the phytase of SEQ ID NO: 1,    wherein the improved property is selected from the group consisting    of increased specific activity; decreased sensitivity to one or more    proteases; increased thermal activity; increased thermal stability,    increased stability in an acidic pH, enhanced stability in a basic    pH, increased feed processing stability.-   12. A phytase of paragraphs 10, wherein the at least one improved    property is a decreased sensitivity to one or more proteases found    in an animal selected from the group consisting of humans, alpaca,    bison, camel, cattle, chicken, poultry, chinchilla, deer, donkey,    duck, fish, frog, goat, goose, fowl, horse, llama, mink, mule,    ostrich, pigeon, reindeer, sheep, shellfish, swine, turkey, yak,    water buffalo cat, chimpanzee, dog, ferret, gerbil, goldfish, guinea    pig, hamster, monkey, parakeet, reptiles and rodents.-   13. A phytase of any of paragraphs 1-11, which has prolonged    activity, as compared to the phytase of SEQ. ID NO: 1, in the    digestive tract of an animal selected from the group consisting of    humans, alpaca, bison, camel, cattle, chicken, poultry, chinchilla,    deer, donkey, duck, fish, frog, goat, goose, fowl, horse, llama,    mink, mule, ostrich, pigeon, reindeer, sheep, shellfish, swine,    turkey, yak, water buffalo cat, chimpanzee, dog, ferret, gerbil,    goldfish, guinea pig, hamster, monkey, parakeet, reptiles and    rodents.-   14. A nucleic acid encoding a phytase of any of paragraphs 1 to 13.-   15. A vector comprising the nucleic acid of paragraph 14.-   16. A host cell comprising the nucleic acid of paragraph 14.-   17. An enzyme composition comprising at least one phytase of any of    paragraphs 1 to 13.-   18. An enzyme composition comprising at least one phytase of any of    paragraphs 1 to 13, wherein said composition is useful in starch    liquefection.-   19. A method for producing a phytase variant of any of paragraphs 1    to 13 in a host cell, comprising    -   a) transforming a host cell with a DNA construct comprising the        nucleic acid encoding the phytase of any of paragraphs 1 to 13,        and    -   b) cultivating the transformed host cell in a suitable culture        medium.-   20. The method according to paragraph 19, wherein the host cell is    selected from the group consisting of a fungal cell, a bacterial    cell or a plant cell.-   21. A phytase variant having phytase activity and an amino acid    sequence that varies from the amino acid sequence of the wild type    Buttiauxella sp. phytase (SEQ ID NO: 1), wherein the amino acid    sequence of the phytase variant comprises at least one variation as    compared with SEQ ID NO: 1, and wherein the variant has a variation    at at least one or more of the following positions: 70, 193, 197,    221 and 407. Preferably, the variant has a variation at at least two    or more of the following positions: 70, 193, 197, 221 and 407.    Preferably, the variant has a variation at at least three or more of    the following positions: 70, 193, 197, 221 and 407. Preferably, the    variant has a variation at at least four or more of the following    positions: 70, 193, 197, 221 and 407. Preferably, the variant has a    variation at at least the following positions: 70, 193, 197, 221 and    407.-   22. A phytase of paragraph 21, wherein the variant has at least the    following variations: N70Y, H193R, F197E, S221P and A407P.-   23. A method for production of food or animal feed comprising a step    of admixing a polypeptide as paragraphed in any of paragraphs 1 to    13 or 21 to 22 or an enzyme composition according to paragraph 17 or    paragraph 18 or prepared by the method of paragraph 19 or 20 with    another food or feed ingredient to form said food or animal feed.-   24. A method for production of food or animal feed comprising a step    of spraying a polypeptide as paragraphed in any of paragraphs 1 to    13 or 21 to 22 or an enzyme composition according to paragraph 17 or    paragraph 18 or prepared by the method of paragraph 19 or 20 in    liquid form onto said food or animal feed.-   25. A method for production of food or animal feed comprising a step    of mixing a polypeptide as paragraphed in any of paragraphs 1 to 13    or 21 to 22 or an enzyme composition according to paragraph 17 or    paragraph 18 or prepared by the method of paragraph 19 or 20 as a    dry product with said food or animal feed.-   26. A method for production of animal feed comprising a step of    admixing a polypeptide as paragraphed in any of paragraphs 1 to 13    or 21 to 22 or an enzyme composition according to paragraph 17 or    paragraph 18 or prepared by the method of paragraph 19 or 20 with    another food or feed ingredient to form said animal feed.-   27. A method for production of animal feed comprising a step of    spraying a polypeptide as paragraphed in any of paragraphs 1 to 13    or 21 to 22 or an enzyme composition according to paragraph 17 or    paragraph 18 or prepared by the method of paragraph 19 or 20 in    liquid form onto said animal feed.-   28. A method for production of animal feed comprising a step of    mixing a polypeptide as paragraphed in any of paragraphs 1 to 13 or    21 to 22 or an enzyme composition according to paragraph 17 or    paragraph 18 or prepared by the method of paragraph 19 or 20 as a    dry product with said animal feed.-   29. A food or animal feed composition comprising either i) a phytase    as paragraphed in any of paragraphs 1 to 13 or 21 to 22 or an enzyme    composition according to paragraph 17 or paragraph 18 or prepared by    the method of paragraph 19 or 20 and/or ii) a food or animal feed    produced by the method according to any one of paragraphs 23 to 28.-   30. An animal feed composition comprising either i) a phytase as    paragraphed in any of paragraphs 1 to 13 or 21 to 22 or an enzyme    composition according to paragraph 17 or paragraph 18 or prepared by    the method of paragraph 19 or 20 and/or ii) an animal feed produced    by the method according to any one of paragraphs 23 to 28.-   31. Use of a phytase polypeptide as paragraphed in any of paragraphs    1 to 13 or 21 to 22 or an enzyme composition according to paragraph    17 or paragraph 18 or prepared by the method of paragraph 19 or 20    in food or animal feed.-   32. Use of a phytase polypeptide as paragraphed in any of paragraphs    1 to 13 or 21 to 22 or an enzyme composition according to paragraph    17 or paragraph 18 or prepared by the method of paragraph 19 or 20    in an animal feed.-   33. A method of reducing the levels of phosphorus in animal manure,    characterized in that an animal is fed with a phytase polypeptide as    paragraphed in any of paragraphs 1 to 13 or 21 to 22 or an enzyme    composition according to paragraph 17 or paragraph 18 or prepared by    the method of paragraph 19 or 20 or a feed according to paragraph 29    or 30, and wherein said phytase is in an amount effective in    converting phytate contained in said animal feed.-   34. Use of a phytase polypeptide as paragraphed in any of paragraphs    1 to 13 or 21 to 22 or an enzyme composition according to paragraph    17 or paragraph 18 or prepared by the method of paragraph 19 or 20    or a feed according to paragraph 29 or 30, in the manufacture of an    animal feed to reduce the levels of phosphorus in manure from the    animal fed with said phytase polypeptide.

All publications mentioned in the above specification, and referencescited in said publications, are herein incorporated by reference.Various modifications and variations of the described methods and systemof the present invention will be apparent to those skilled in the artwithout departing from the scope and spirit of the present invention.Although the invention has been described in connection with specificpreferred embodiments, it should be understood that the invention asclaimed should not be unduly limited to such specific embodiments.Indeed, various modifications of the described modes for carrying outthe invention which are obvious to those skilled in molecular biology orrelated fields are intended to be within the scope of the followingclaims.

What is claimed is: 1-15. (canceled)
 16. A phytase variant havingphytase activity and an amino acid sequence that varies from the aminoacid sequence of wild type Buttiauxella sp. phytase (SEQ ID NO: 1),wherein the amino acid sequence of the phytase variant comprises atleast one variation as compared with SEQ ID NO: 1, and wherein thephytase sequence variation comprises a) N37Y, S75P, A89T, D92A, T134I,H160R, F164E, T171V, T176K, A178P, S188P, G192A, K198R, K207E, A209S,S248L, Q256Y, A261E, N270K, A374P b) N37Y, G77S, A89T, D92A, T134I,H160R, F164E, T171V, T176K, A178P, S188P, G192A, K198R, K207E, A209S,S248L, Q256Y, A261E, N270K, A374P c) N37Y, S75P, Q76R, A89T, D92A,T134I, H160R, F164E, T171I, T176K, A178P, S188P, G192A, K207E, A209S,A235V, S248L, Q256Y, A261E, N270K, A374P d) N37Y, A89T, D92A, T134I,F164E, T171V, T176K, A178P, G192A, K207E, A209S, A235V, S248L, Q256P,A261E, N270K, A374P e) S75P, Q76R, A89T, D92A, T134I, H160R, F164E,T171I, T176K, A178P, S188P, G192A, K207E, A209S, S248L, Q256Y, A261E,N270K, A374P f) N37Y, Q76R, A89T, D92A, T134I, H160R, F164E, T171I,T176K, A178P, S188P, G192A, K207E, A209S, S248L, Q256Y, A261E, N270K,A374P g) N37Y, Q76R, A89T, D92A, T134I, F164S, T171V, T176K, A178P,S188P, G192A, K207E, A209S, A235V, S248L, Q256A, A261E, N270K, A374P h)S75P, A89T, D92A, T134I, F164E, T171V, T176K, A178P, S188P, G192A,K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, A374P i) S75P, Q76R,A89T, D92A, T134I, H160R, F164E, T171V, T176K, A178P, S188P, G192A,K207E, A209S, A235V, S248L, Q256Y, A261E, N270K, P367L, A374P j) N37Y,A89T, D92A, T134I, F164E, T171I, T176K, A178P, G192A, K207E, A209S,A235V, S248L, Q256Y, A261E, N270K, A374P k) N37Y, Q76R, A89T, D92A,T134I, F164E, T171V, T176K, A178P, G192A, K207E, A209S, S248L, Q256Y,A261E, N270K, A374P l) N37Y, Q76R, A89T, D92A, T134I, F164E, T171V,T176K, A178P, G192A, K207E, A209S, S248L, Q256A, A261E, N270K, A374P m)N37Y, S75P, Q76R, A89T, D92A, T134I, F164E, T171V, T176K, A178P, K207E,A209S, A235V, S248L, Q256A, A261E, N270K, A374P n) N37Y, S75P, A89T,D92A, T134I, H160R, F164E, T171V, T176K, A178P, K207E, A209S, A235V,S248L, Q256Y, A261E, N270K, A374P o) N37Y, A89T, D92A, T134I, H160R,F164S, T171I, T176K, A178P, S188P, G192A, K207E, A209S, A235V, S248L,Q256E, A261E, N270K, A374P p) A89T, D92A, T134I, H160R, F164E, T171V,T176K, A178P, G192A, K207E, A209S, A235V, S248L, Q256Y, A261E, N270K,A374P q) N37Y, S75P, A89T, D92A, T134I, H160R, F164S, T171V, T176K,A178P, S188P, K207E, A209S, S248L, Q256H, A261E, N270K, A374P r) N37Y,S75P, A89T, D92A, T134I, F164S, T171V, T176K, A178P, S188P, G192A,K207E, A209S, S248L, Q256A, A261E, N270K, A374P s) S75P, Q76R, A89T,D92A, T134I, H160R, F164E, T171V, T176K, A178P, G192A, K207E, A209S,S248L, Q256A, A261E, N270K, A374P; or t) N37Y, Q76R, A89T, D92A, T134I,H160R, F164S, T171V, T176K, A178P, G192A, K207E, A209S, A235V, S248L,Q256Y, A261E, N270K, A374P.
 17. The phytase variant of claim 16, whereinthe phytase sequence variation comprises N37Y, S75P, Q76R, A89T, D92A,T134I, H160R, F164E, T171I, T176K, A178P, S188P, G192A, K207E, A209S,A235V, S248L, Q256Y, A261E, N270K, A374P.
 18. A phytase which has atleast a minimum percent sequence identity and/or percent homology to thephytase of claim 16, wherein the minimum percent identity and/orhomology is at least 50%, at least 60%, at least 75%, at least 80%, atleast 85%, at least 90%, at least 93%, at least 95%, at least 96%, atleast 97%, at least 98% or at least 99%.
 19. A phytase variant havingphytase activity and an amino acid sequence that varies from the aminoacid sequence of the wild type Buttiauxella sp. phytase (SEQ ID NO: 1),wherein the amino acid sequence of the phytase variant comprises atleast one variation as compared with SEQ ID NO: 1, and wherein thevariant has a variation at at least any one of the following positions:70, 193, 197, 221 and
 407. 20. A phytase of claim 19, wherein thevariant has at least the following variations: N70Y, H193R, F197E, S221Pand A407P. 21-26. (canceled)
 27. A nucleic acid encoding a phytase ofclaim
 16. 28. A vector comprising the nucleic acid of claim
 27. 29. Ahost cell comprising the vector of claim
 28. 30. A method of producing aphytase variant of claim 16 in a host cell, comprising a) transforming ahost cell with a DNA construct comprising the nucleic acid encoding thephytase of claim 16, and b) cultivating the transformed host cell in asuitable culture medium.
 31. The method according to claim 19, whereinthe host cell is a fungal cell, a bacterial cell or a plant cell.
 32. Aphytase prepared by the method according to claim 31 or claim
 31. 33. Anenzyme composition comprising at least one phytase of claim 16 includingadditionally one or more of a glucoamylase, an alpha-amylase, aprotease, a pullulanase, an isoamylase, a cellulase, a hemicellulase, axylanase, a cyclodextrin glycotransferase, a lipase, a laccase, anoxidase, an esterase, a cutinase, another phytase or any combinationsthereof.
 34. The enzyme composition of claim 33, wherein analpha-amylase is included. 35-57. (canceled)